diff --git a/NEWS b/NEWS
index 4c94a989..71ef7336 100644
--- a/NEWS
+++ b/NEWS
@@ -15,6 +15,10 @@ What's new in psycopg 2.4.5
     Regression introduced in 2.4.4 (ticket #100).
   - Added support for 'inet' arrays.
   - Fixed 'commit()' concurrency problem (ticket #103).
+  - Codebase cleaned up using the GCC Python plugin's static analysis
+    tool, which has revealed several unchecked return values, possible
+    NULL dereferences, reference counting problems. Many thanks to David
+    Malcolm for the useful tool and the assistance provided using it.
 
 
 What's new in psycopg 2.4.4
diff --git a/psycopg/adapter_binary.c b/psycopg/adapter_binary.c
index 2574c603..b08c1447 100644
--- a/psycopg/adapter_binary.c
+++ b/psycopg/adapter_binary.c
@@ -65,6 +65,13 @@ binary_quote(binaryObject *self)
     int got_view = 0;
 #endif
 
+    /* Allow Binary(None) to work */
+    if (self->wrapped == Py_None) {
+        Py_INCREF(psyco_null);
+        rv = psyco_null;
+        goto exit;
+    }
+
     /* if we got a plain string or a buffer we escape it and save the buffer */
 
 #if HAS_MEMORYVIEW
@@ -93,7 +100,7 @@ binary_quote(binaryObject *self)
 
     /* escape and build quoted buffer */
 
-    to = (char *)binary_escape((unsigned char*)buffer, (size_t) buffer_len,
+    to = (char *)binary_escape((unsigned char*)buffer, (size_t)buffer_len,
         &len, self->conn ? ((connectionObject*)self->conn)->pgconn : NULL);
     if (to == NULL) {
         PyErr_NoMemory();
@@ -113,12 +120,6 @@ exit:
     if (got_view) { PyBuffer_Release(&view); }
 #endif
 
-    /* Allow Binary(None) to work */
-    if (self->wrapped == Py_None) {
-        Py_INCREF(psyco_null);
-        rv = psyco_null;
-    }
-
     /* if the wrapped object is not bytes or a buffer, this is an error */
     if (!rv && !PyErr_Occurred()) {
         PyErr_Format(PyExc_TypeError, "can't escape %s to binary",
@@ -149,16 +150,14 @@ binary_str(binaryObject *self)
 static PyObject *
 binary_prepare(binaryObject *self, PyObject *args)
 {
-    connectionObject *conn;
+    PyObject *conn;
 
-    if (!PyArg_ParseTuple(args, "O", &conn))
+    if (!PyArg_ParseTuple(args, "O!", &connectionType, &conn))
         return NULL;
 
     Py_XDECREF(self->conn);
-    if (conn) {
-        self->conn = (PyObject*)conn;
-        Py_INCREF(self->conn);
-    }
+    self->conn = conn;
+    Py_INCREF(self->conn);
 
     Py_INCREF(Py_None);
     return Py_None;
diff --git a/psycopg/adapter_datetime.c b/psycopg/adapter_datetime.c
index 5850be8f..bf31cfab 100644
--- a/psycopg/adapter_datetime.c
+++ b/psycopg/adapter_datetime.c
@@ -427,6 +427,10 @@ psyco_DateFromTicks(PyObject *self, PyObject *args)
             Py_DECREF(args);
         }
     }
+	else {
+		PyErr_SetString(InterfaceError, "failed localtime call");
+	}
+
     return res;
 }
 
@@ -451,6 +455,10 @@ psyco_TimeFromTicks(PyObject *self, PyObject *args)
             Py_DECREF(args);
         }
     }
+	else {
+		PyErr_SetString(InterfaceError, "failed localtime call");
+	}
+
     return res;
 }
 
@@ -473,6 +481,9 @@ psyco_TimestampFromTicks(PyObject *self, PyObject *args)
             tm.tm_hour, tm.tm_min, (double)tm.tm_sec + ticks,
             pyPsycopgTzLOCAL);
     }
+	else {
+		PyErr_SetString(InterfaceError, "failed localtime call");
+	}
 
     return res;
 }
diff --git a/psycopg/adapter_list.c b/psycopg/adapter_list.c
index cbb75422..d97ecfb1 100644
--- a/psycopg/adapter_list.c
+++ b/psycopg/adapter_list.c
@@ -98,9 +98,9 @@ list_getquoted(listObject *self, PyObject *args)
 static PyObject *
 list_prepare(listObject *self, PyObject *args)
 {
-    connectionObject *conn;
+    PyObject *conn;
 
-    if (!PyArg_ParseTuple(args, "O", &conn))
+    if (!PyArg_ParseTuple(args, "O!", &connectionType, &conn))
         return NULL;
 
     /* note that we don't copy the encoding from the connection, but take a
@@ -109,7 +109,7 @@ list_prepare(listObject *self, PyObject *args)
        work even without a connection to the backend. */
     Py_CLEAR(self->connection);
     Py_INCREF(conn);
-    self->connection = (PyObject*)conn;
+    self->connection = conn;
 
     Py_INCREF(Py_None);
     return Py_None;
diff --git a/psycopg/adapter_qstring.c b/psycopg/adapter_qstring.c
index a9d4ec6e..773cfa0d 100644
--- a/psycopg/adapter_qstring.c
+++ b/psycopg/adapter_qstring.c
@@ -35,7 +35,7 @@
 
 /* qstring_quote - do the quote process on plain and unicode strings */
 
-static PyObject *
+BORROWED static PyObject *
 qstring_quote(qstringObject *self)
 {
     PyObject *str;
@@ -124,24 +124,22 @@ qstring_str(qstringObject *self)
 static PyObject *
 qstring_prepare(qstringObject *self, PyObject *args)
 {
-    connectionObject *conn;
+    PyObject *conn;
 
-    if (!PyArg_ParseTuple(args, "O", &conn))
+    if (!PyArg_ParseTuple(args, "O!", &connectionType, &conn))
         return NULL;
 
     /* we bother copying the encoding only if the wrapped string is unicode,
        we don't need the encoding if that's not the case */
     if (PyUnicode_Check(self->wrapped)) {
         if (self->encoding) free(self->encoding);
-        self->encoding = strdup(conn->codec);
-        Dprintf("qstring_prepare: set encoding to %s", conn->codec);
+        self->encoding = strdup(((connectionObject *)conn)->codec);
+        Dprintf("qstring_prepare: set encoding to %s", self->encoding);
     }
 
     Py_CLEAR(self->conn);
-    if (conn) {
-        Py_INCREF(conn);
-        self->conn = (PyObject*)conn;
-    }
+    Py_INCREF(conn);
+    self->conn = conn;
 
     Py_INCREF(Py_None);
     return Py_None;
diff --git a/psycopg/bytes_format.c b/psycopg/bytes_format.c
index 1e729e49..68662075 100644
--- a/psycopg/bytes_format.c
+++ b/psycopg/bytes_format.c
@@ -86,7 +86,7 @@
 
 /* Helpers for formatstring */
 
-Py_LOCAL_INLINE(PyObject *)
+BORROWED Py_LOCAL_INLINE(PyObject *)
 getnextarg(PyObject *args, Py_ssize_t arglen, Py_ssize_t *p_argidx)
 {
     Py_ssize_t argidx = *p_argidx;
diff --git a/psycopg/config.h b/psycopg/config.h
index 2112043b..f3094493 100644
--- a/psycopg/config.h
+++ b/psycopg/config.h
@@ -160,4 +160,33 @@ static double round(double num)
 #define isinf(x) (!finite((x)) && (x)==(x))
 #endif
 
+/* decorators for the gcc cpychecker plugin */
+#if defined(WITH_CPYCHECKER_RETURNS_BORROWED_REF_ATTRIBUTE)
+#define BORROWED \
+    __attribute__((cpychecker_returns_borrowed_ref))
+#else
+#define BORROWED
+#endif
+
+#if defined(WITH_CPYCHECKER_STEALS_REFERENCE_TO_ARG_ATTRIBUTE)
+#define STEALS(n) \
+    __attribute__((cpychecker_steals_reference_to_arg(n)))
+#else
+#define STEALS(n)
+#endif
+
+#if defined(WITH_CPYCHECKER_NEGATIVE_RESULT_SETS_EXCEPTION_ATTRIBUTE)
+#define RAISES_NEG \
+    __attribute__((cpychecker_negative_result_sets_exception))
+#else
+#define RAISES_NEG
+#endif
+
+#if defined(WITH_CPYCHECKER_SETS_EXCEPTION_ATTRIBUTE)
+#define RAISES \
+    __attribute__((cpychecker_sets_exception))
+#else
+#define RAISES
+#endif
+
 #endif /* !defined(PSYCOPG_CONFIG_H) */
diff --git a/psycopg/connection.h b/psycopg/connection.h
index 9a9ea420..9647ffd2 100644
--- a/psycopg/connection.h
+++ b/psycopg/connection.h
@@ -131,27 +131,27 @@ typedef struct {
 /* C-callable functions in connection_int.c and connection_ext.c */
 HIDDEN PyObject *conn_text_from_chars(connectionObject *pgconn, const char *str);
 HIDDEN int  conn_get_standard_conforming_strings(PGconn *pgconn);
-HIDDEN int  conn_get_isolation_level(connectionObject *self);
+RAISES_NEG HIDDEN int  conn_get_isolation_level(connectionObject *self);
 HIDDEN int  conn_get_protocol_version(PGconn *pgconn);
 HIDDEN int  conn_get_server_version(PGconn *pgconn);
 HIDDEN PGcancel *conn_get_cancel(PGconn *pgconn);
 HIDDEN void conn_notice_process(connectionObject *self);
 HIDDEN void conn_notice_clean(connectionObject *self);
 HIDDEN void conn_notifies_process(connectionObject *self);
-HIDDEN int  conn_setup(connectionObject *self, PGconn *pgconn);
+RAISES_NEG HIDDEN int  conn_setup(connectionObject *self, PGconn *pgconn);
 HIDDEN int  conn_connect(connectionObject *self, long int async);
 HIDDEN void conn_close(connectionObject *self);
-HIDDEN int  conn_commit(connectionObject *self);
-HIDDEN int  conn_rollback(connectionObject *self);
-HIDDEN int  conn_set_session(connectionObject *self, const char *isolevel,
+RAISES_NEG HIDDEN int  conn_commit(connectionObject *self);
+RAISES_NEG HIDDEN int  conn_rollback(connectionObject *self);
+RAISES_NEG HIDDEN int  conn_set_session(connectionObject *self, const char *isolevel,
                                  const char *readonly, const char *deferrable,
                                  int autocommit);
 HIDDEN int  conn_set_autocommit(connectionObject *self, int value);
-HIDDEN int  conn_switch_isolation_level(connectionObject *self, int level);
-HIDDEN int  conn_set_client_encoding(connectionObject *self, const char *enc);
+RAISES_NEG HIDDEN int  conn_switch_isolation_level(connectionObject *self, int level);
+RAISES_NEG HIDDEN int  conn_set_client_encoding(connectionObject *self, const char *enc);
 HIDDEN int  conn_poll(connectionObject *self);
-HIDDEN int  conn_tpc_begin(connectionObject *self, XidObject *xid);
-HIDDEN int  conn_tpc_command(connectionObject *self,
+RAISES_NEG HIDDEN int  conn_tpc_begin(connectionObject *self, XidObject *xid);
+RAISES_NEG HIDDEN int  conn_tpc_command(connectionObject *self,
                              const char *cmd, XidObject *xid);
 HIDDEN PyObject *conn_tpc_recover(connectionObject *self);
 
diff --git a/psycopg/connection_int.c b/psycopg/connection_int.c
index 2395c00c..8c8fed47 100644
--- a/psycopg/connection_int.c
+++ b/psycopg/connection_int.c
@@ -120,8 +120,16 @@ conn_notice_process(connectionObject *self)
 
         /* Respect the order in which notices were produced,
            because in notice_list they are reversed (see ticket #9) */
-        PyList_Insert(self->notice_list, nnotices, msg);
-        Py_DECREF(msg);
+        if (msg) {
+            PyList_Insert(self->notice_list, nnotices, msg);
+            Py_DECREF(msg);
+        }
+        else {
+            /* We don't really have a way to report errors, so gulp it.
+             * The function should only fail for out of memory, so we are
+             * likely going to die anyway. */
+            PyErr_Clear();
+        }
 
         notice = notice->next;
     }
@@ -242,19 +250,20 @@ conn_get_standard_conforming_strings(PGconn *pgconn)
 
 /* Remove irrelevant chars from encoding name and turn it uppercase.
  *
- * Return a buffer allocated on Python heap,
- * NULL and set an exception on error.
+ * Return a buffer allocated on Python heap into 'clean' and return 0 on
+ * success, otherwise return -1 and set an exception.
  */
-static char *
-clean_encoding_name(const char *enc)
+RAISES_NEG static int
+clear_encoding_name(const char *enc, char **clean)
 {
     const char *i = enc;
-    char *rv, *j;
+    char *j, *buf;
+    int rv = -1;
 
     /* convert to upper case and remove '-' and '_' from string */
-    if (!(j = rv = PyMem_Malloc(strlen(enc) + 1))) {
+    if (!(j = buf = PyMem_Malloc(strlen(enc) + 1))) {
         PyErr_NoMemory();
-        return NULL;
+        goto exit;
     }
 
     while (*i) {
@@ -267,25 +276,28 @@ clean_encoding_name(const char *enc)
     }
     *j = '\0';
 
-    Dprintf("clean_encoding_name: %s -> %s", enc, rv);
+    Dprintf("clear_encoding_name: %s -> %s", enc, buf);
+    *clean = buf;
+    rv = 0;
 
+exit:
     return rv;
 }
 
 /* Convert a PostgreSQL encoding to a Python codec.
  *
- * Return a new copy of the codec name allocated on the Python heap,
- * NULL with exception in case of error.
+ * Set 'codec' to a new copy of the codec name allocated on the Python heap.
+ * Return 0 in case of success, else -1 and set an exception.
  *
  * 'enc' should be already normalized (uppercase, no - or _).
  */
-static char *
-conn_encoding_to_codec(const char *enc)
+RAISES_NEG static int
+conn_encoding_to_codec(const char *enc, char **codec)
 {
     char *tmp;
     Py_ssize_t size;
     PyObject *pyenc = NULL;
-    char *rv = NULL;
+    int rv = -1;
 
     /* Find the Py codec name from the PG encoding */
     if (!(pyenc = PyDict_GetItemString(psycoEncodings, enc))) {
@@ -305,7 +317,7 @@ conn_encoding_to_codec(const char *enc)
     }
 
     /* have our own copy of the python codec name */
-    rv = psycopg_strdup(tmp, size);
+    rv = psycopg_strdup(codec, tmp, size);
 
 exit:
     Py_XDECREF(pyenc);
@@ -320,7 +332,7 @@ exit:
  *
  * Return 0 on success, else nonzero.
  */
-static int
+RAISES_NEG static int
 conn_read_encoding(connectionObject *self, PGconn *pgconn)
 {
     char *enc = NULL, *codec = NULL;
@@ -335,12 +347,12 @@ conn_read_encoding(connectionObject *self, PGconn *pgconn)
         goto exit;
     }
 
-    if (!(enc = clean_encoding_name(tmp))) {
+    if (0 > clear_encoding_name(tmp, &enc)) {
         goto exit;
     }
 
     /* Look for this encoding in Python codecs. */
-    if (!(codec = conn_encoding_to_codec(enc))) {
+    if (0 > conn_encoding_to_codec(enc, &codec)) {
         goto exit;
     }
 
@@ -362,7 +374,7 @@ exit:
 }
 
 
-int
+RAISES_NEG int
 conn_get_isolation_level(connectionObject *self)
 {
     PGresult *pgres = NULL;
@@ -456,7 +468,7 @@ conn_is_datestyle_ok(PGconn *pgconn)
 
 /* conn_setup - setup and read basic information about the connection */
 
-int
+RAISES_NEG int
 conn_setup(connectionObject *self, PGconn *pgconn)
 {
     PGresult *pgres = NULL;
@@ -470,7 +482,7 @@ conn_setup(connectionObject *self, PGconn *pgconn)
         return -1;
     }
 
-    if (conn_read_encoding(self, pgconn)) {
+    if (0 > conn_read_encoding(self, pgconn)) {
         return -1;
     }
 
@@ -484,7 +496,7 @@ conn_setup(connectionObject *self, PGconn *pgconn)
     pthread_mutex_lock(&self->lock);
     Py_BLOCK_THREADS;
 
-    if (psyco_green() && (pq_set_non_blocking(self, 1, 1) != 0)) {
+    if (psyco_green() && (0 > pq_set_non_blocking(self, 1))) {
         return -1;
     }
 
@@ -762,7 +774,7 @@ _conn_poll_setup_async(connectionObject *self)
     switch (self->status) {
     case CONN_STATUS_CONNECTING:
         /* Set the connection to nonblocking now. */
-        if (pq_set_non_blocking(self, 1, 1) != 0) {
+        if (pq_set_non_blocking(self, 1) != 0) {
             break;
         }
 
@@ -773,7 +785,7 @@ _conn_poll_setup_async(connectionObject *self)
             PyErr_SetString(InterfaceError, "only protocol 3 supported");
             break;
         }
-        if (conn_read_encoding(self, self->pgconn)) {
+        if (0 > conn_read_encoding(self, self->pgconn)) {
             break;
         }
         self->cancel = conn_get_cancel(self->pgconn);
@@ -942,7 +954,7 @@ conn_close(connectionObject *self)
 
 /* conn_commit - commit on a connection */
 
-int
+RAISES_NEG int
 conn_commit(connectionObject *self)
 {
     int res;
@@ -953,7 +965,7 @@ conn_commit(connectionObject *self)
 
 /* conn_rollback - rollback a connection */
 
-int
+RAISES_NEG int
 conn_rollback(connectionObject *self)
 {
     int res;
@@ -962,7 +974,7 @@ conn_rollback(connectionObject *self)
     return res;
 }
 
-int
+RAISES_NEG int
 conn_set_session(connectionObject *self,
         const char *isolevel, const char *readonly, const char *deferrable,
         int autocommit)
@@ -1035,7 +1047,7 @@ conn_set_autocommit(connectionObject *self, int value)
 
 /* conn_switch_isolation_level - switch isolation level on the connection */
 
-int
+RAISES_NEG int
 conn_switch_isolation_level(connectionObject *self, int level)
 {
     PGresult *pgres = NULL;
@@ -1117,12 +1129,12 @@ endlock:
 
 /* conn_set_client_encoding - switch client encoding on connection */
 
-int
+RAISES_NEG int
 conn_set_client_encoding(connectionObject *self, const char *enc)
 {
     PGresult *pgres = NULL;
     char *error = NULL;
-    int res = 1;
+    int res = -1;
     char *codec = NULL;
     char *clean_enc = NULL;
 
@@ -1131,8 +1143,8 @@ conn_set_client_encoding(connectionObject *self, const char *enc)
     if (strcmp(self->encoding, enc) == 0) return 0;
 
     /* We must know what python codec this encoding is. */
-    if (!(clean_enc = clean_encoding_name(enc))) { goto exit; }
-    if (!(codec = conn_encoding_to_codec(clean_enc))) { goto exit; }
+    if (0 > clear_encoding_name(enc, &clean_enc)) { goto exit; }
+    if (0 > conn_encoding_to_codec(clean_enc, &codec)) { goto exit; }
 
     Py_BEGIN_ALLOW_THREADS;
     pthread_mutex_lock(&self->lock);
@@ -1190,7 +1202,7 @@ exit:
  * in regular transactions, as PostgreSQL won't even know we are in a TPC
  * until PREPARE. */
 
-int
+RAISES_NEG int
 conn_tpc_begin(connectionObject *self, XidObject *xid)
 {
     PGresult *pgres = NULL;
@@ -1224,7 +1236,7 @@ conn_tpc_begin(connectionObject *self, XidObject *xid)
  * The function doesn't change the connection state as it can be used
  * for many commands and for recovered transactions. */
 
-int
+RAISES_NEG int
 conn_tpc_command(connectionObject *self, const char *cmd, XidObject *xid)
 {
     PGresult *pgres = NULL;
diff --git a/psycopg/connection_type.c b/psycopg/connection_type.c
index 09ced62e..4e5b6170 100644
--- a/psycopg/connection_type.c
+++ b/psycopg/connection_type.c
@@ -526,7 +526,7 @@ psyco_conn_set_session(connectionObject *self, PyObject *args, PyObject *kwargs)
         if (-1 == c_autocommit) { return NULL; }
     }
 
-    if (0 != conn_set_session(self,
+    if (0 > conn_set_session(self,
             c_isolevel, c_readonly, c_deferrable, c_autocommit)) {
         return NULL;
     }
@@ -548,7 +548,7 @@ psyco_conn_autocommit_get(connectionObject *self)
     return ret;
 }
 
-static PyObject *
+BORROWED static PyObject *
 _psyco_conn_autocommit_set_checks(connectionObject *self)
 {
     /* wrapper to use the EXC_IF macros.
@@ -635,7 +635,7 @@ psyco_conn_set_client_encoding(connectionObject *self, PyObject *args)
 
     if (!PyArg_ParseTuple(args, "s", &enc)) return NULL;
 
-    if (conn_set_client_encoding(self, enc) == 0) {
+    if (conn_set_client_encoding(self, enc) >= 0) {
         Py_INCREF(Py_None);
         rv = Py_None;
     }
@@ -699,8 +699,8 @@ psyco_conn_get_parameter_status(connectionObject *self, PyObject *args)
 static PyObject *
 psyco_conn_lobject(connectionObject *self, PyObject *args, PyObject *keywds)
 {
-    Oid oid=InvalidOid, new_oid=InvalidOid;
-    char *new_file = NULL;
+    int oid = (int)InvalidOid, new_oid = (int)InvalidOid;
+    const char *new_file = NULL;
     const char *smode = "";
     PyObject *factory = (PyObject *)&lobjectType;
     PyObject *obj;
@@ -752,7 +752,7 @@ psyco_conn_lobject(connectionObject *self, PyObject *args, PyObject *keywds)
 "get_backend_pid() -- Get backend process id."
 
 static PyObject *
-psyco_conn_get_backend_pid(connectionObject *self)
+psyco_conn_get_backend_pid(connectionObject *self, PyObject *args)
 {
     EXC_IF_CONN_CLOSED(self);
 
@@ -765,7 +765,7 @@ psyco_conn_get_backend_pid(connectionObject *self)
 "reset() -- Reset current connection to defaults."
 
 static PyObject *
-psyco_conn_reset(connectionObject *self)
+psyco_conn_reset(connectionObject *self, PyObject *args)
 {
     int res;
 
@@ -793,7 +793,7 @@ psyco_conn_get_exception(PyObject *self, void *closure)
 }
 
 static PyObject *
-psyco_conn_poll(connectionObject *self)
+psyco_conn_poll(connectionObject *self, PyObject *args)
 {
     int res;
 
@@ -815,7 +815,7 @@ psyco_conn_poll(connectionObject *self)
 "fileno() -> int -- Return file descriptor associated to database connection."
 
 static PyObject *
-psyco_conn_fileno(connectionObject *self)
+psyco_conn_fileno(connectionObject *self, PyObject *args)
 {
     long int socket;
 
@@ -834,7 +834,7 @@ psyco_conn_fileno(connectionObject *self)
  "executing an asynchronous operation."
 
 static PyObject *
-psyco_conn_isexecuting(connectionObject *self)
+psyco_conn_isexecuting(connectionObject *self, PyObject *args)
 {
     /* synchronous connections will always return False */
     if (self->async == 0) {
@@ -866,7 +866,7 @@ psyco_conn_isexecuting(connectionObject *self)
 "cancel() -- cancel the current operation"
 
 static PyObject *
-psyco_conn_cancel(connectionObject *self)
+psyco_conn_cancel(connectionObject *self, PyObject *args)
 {
     char errbuf[256];
 
diff --git a/psycopg/cursor.h b/psycopg/cursor.h
index eecaa8ff..723bd170 100644
--- a/psycopg/cursor.h
+++ b/psycopg/cursor.h
@@ -85,7 +85,7 @@ struct cursorObject {
 
 
 /* C-callable functions in cursor_int.c and cursor_ext.c */
-HIDDEN PyObject *curs_get_cast(cursorObject *self, PyObject *oid);
+BORROWED HIDDEN PyObject *curs_get_cast(cursorObject *self, PyObject *oid);
 HIDDEN void curs_reset(cursorObject *self);
 
 /* exception-raising macros */
diff --git a/psycopg/cursor_int.c b/psycopg/cursor_int.c
index 40e0bae3..1ac3f550 100644
--- a/psycopg/cursor_int.c
+++ b/psycopg/cursor_int.c
@@ -38,7 +38,7 @@
  * Return a borrowed reference.
  */
 
-PyObject *
+BORROWED PyObject *
 curs_get_cast(cursorObject *self, PyObject *oid)
 {
     PyObject *cast;
diff --git a/psycopg/cursor_type.c b/psycopg/cursor_type.c
index 4de01634..bcbefc5f 100644
--- a/psycopg/cursor_type.c
+++ b/psycopg/cursor_type.c
@@ -79,7 +79,7 @@ exit:
 
 /* mogrify a query string and build argument array or dict */
 
-static int
+RAISES_NEG static int
 _mogrify(PyObject *var, PyObject *fmt, cursorObject *curs, PyObject **new)
 {
     PyObject *key, *value, *n;
@@ -221,7 +221,10 @@ _mogrify(PyObject *var, PyObject *fmt, cursorObject *curs, PyObject **new)
             }
 
             if (n == NULL) {
-                n = PyTuple_New(PyObject_Length(var));
+                if (!(n = PyTuple_New(PyObject_Length(var)))) {
+                    Py_DECREF(value);
+                    return -1;
+                }
             }
 
             /* let's have d point just after the '%' */
@@ -360,11 +363,12 @@ _psyco_curs_merge_query_args(cursorObject *self,
 #define psyco_curs_execute_doc \
 "execute(query, vars=None) -- Execute query with bound vars."
 
-static int
+RAISES_NEG static int
 _psyco_curs_execute(cursorObject *self,
                     PyObject *operation, PyObject *vars, long int async)
 {
-    int res = 0;
+    int res = -1;
+    int tmp;
     PyObject *fquery, *cvt = NULL;
 
     operation = _psyco_curs_validate_sql_basic(self, operation);
@@ -372,7 +376,7 @@ _psyco_curs_execute(cursorObject *self,
     /* Any failure from here forward should 'goto fail' rather than 'return 0'
        directly. */
 
-    if (operation == NULL) { goto fail; }
+    if (operation == NULL) { goto exit; }
 
     IFCLEARPGRES(self->pgres);
 
@@ -389,12 +393,12 @@ _psyco_curs_execute(cursorObject *self,
 
     if (vars && vars != Py_None)
     {
-        if(_mogrify(vars, operation, self, &cvt) == -1) { goto fail; }
+        if (0 > _mogrify(vars, operation, self, &cvt)) { goto exit; }
     }
 
     if (vars && cvt) {
         if (!(fquery = _psyco_curs_merge_query_args(self, operation, cvt))) {
-            goto fail;
+            goto exit;
         }
 
         if (self->name != NULL) {
@@ -428,25 +432,20 @@ _psyco_curs_execute(cursorObject *self,
 
     /* At this point, the SQL statement must be str, not unicode */
 
-    res = pq_execute(self, Bytes_AS_STRING(self->query), async);
-    Dprintf("psyco_curs_execute: res = %d, pgres = %p", res, self->pgres);
-    if (res == -1) { goto fail; }
+    tmp = pq_execute(self, Bytes_AS_STRING(self->query), async);
+    Dprintf("psyco_curs_execute: res = %d, pgres = %p", tmp, self->pgres);
+    if (tmp < 0) { goto exit; }
 
-    res = 1; /* Success */
-    goto cleanup;
+    res = 0; /* Success */
 
-    fail:
-        res = 0;
-        /* Fall through to cleanup */
-    cleanup:
-        /* Py_XDECREF(operation) is safe because the original reference passed
-           by the caller was overwritten with either NULL or a new
-           reference */
-        Py_XDECREF(operation);
+exit:
+    /* Py_XDECREF(operation) is safe because the original reference passed
+       by the caller was overwritten with either NULL or a new
+       reference */
+    Py_XDECREF(operation);
+    Py_XDECREF(cvt);
 
-        Py_XDECREF(cvt);
-
-        return res;
+    return res;
 }
 
 static PyObject *
@@ -480,13 +479,13 @@ psyco_curs_execute(cursorObject *self, PyObject *args, PyObject *kwargs)
     EXC_IF_ASYNC_IN_PROGRESS(self, execute);
     EXC_IF_TPC_PREPARED(self->conn, execute);
 
-    if (_psyco_curs_execute(self, operation, vars, self->conn->async)) {
-        Py_INCREF(Py_None);
-        return Py_None;
-    }
-    else {
+    if (0 > _psyco_curs_execute(self, operation, vars, self->conn->async)) {
         return NULL;
     }
+
+    /* success */
+    Py_INCREF(Py_None);
+    return Py_None;
 }
 
 #define psyco_curs_executemany_doc \
@@ -525,7 +524,7 @@ psyco_curs_executemany(cursorObject *self, PyObject *args, PyObject *kwargs)
     }
 
     while ((v = PyIter_Next(vars)) != NULL) {
-        if (_psyco_curs_execute(self, operation, v, 0) == 0) {
+        if (0 > _psyco_curs_execute(self, operation, v, 0)) {
             Py_DECREF(v);
             Py_XDECREF(iter);
             return NULL;
@@ -572,7 +571,7 @@ _psyco_curs_mogrify(cursorObject *self,
 
     if (vars && vars != Py_None)
     {
-        if (_mogrify(vars, operation, self, &cvt) == -1) {
+        if (0 > _mogrify(vars, operation, self, &cvt)) {
             goto cleanup;
         }
     }
@@ -648,7 +647,7 @@ psyco_curs_cast(cursorObject *self, PyObject *args)
 "default) or using the sequence factory previously set in the\n" \
 "`row_factory` attribute. Return `!None` when no more data is available.\n"
 
-static int
+RAISES_NEG static int
 _psyco_curs_prefetch(cursorObject *self)
 {
     int i = 0;
@@ -665,13 +664,14 @@ _psyco_curs_prefetch(cursorObject *self)
     return i;
 }
 
-static PyObject *
+RAISES_NEG static int
 _psyco_curs_buildrow_fill(cursorObject *self, PyObject *res,
                           int row, int n, int istuple)
 {
     int i, len, err;
     const char *str;
     PyObject *val;
+    int rv = -1;
 
     for (i=0; i < n; i++) {
         if (PQgetisnull(self->pgres, row, i)) {
@@ -686,59 +686,59 @@ _psyco_curs_buildrow_fill(cursorObject *self, PyObject *res,
         Dprintf("_psyco_curs_buildrow: row %ld, element %d, len %d",
                 self->row, i, len);
 
-        val = typecast_cast(PyTuple_GET_ITEM(self->casts, i), str, len,
-                            (PyObject*)self);
+        if (!(val = typecast_cast(PyTuple_GET_ITEM(self->casts, i), str, len,
+                            (PyObject*)self))) {
+            goto exit;
+        }
 
-        if (val) {
-            Dprintf("_psyco_curs_buildrow: val->refcnt = "
-                FORMAT_CODE_PY_SSIZE_T,
-                Py_REFCNT(val)
-              );
-            if (istuple) {
-                PyTuple_SET_ITEM(res, i, val);
-            }
-            else {
-                err = PySequence_SetItem(res, i, val);
-                Py_DECREF(val);
-                if (err == -1) {
-                    Py_DECREF(res);
-                    res = NULL;
-                    break;
-                }
-            }
+        Dprintf("_psyco_curs_buildrow: val->refcnt = "
+            FORMAT_CODE_PY_SSIZE_T,
+            Py_REFCNT(val)
+          );
+        if (istuple) {
+            PyTuple_SET_ITEM(res, i, val);
         }
         else {
-            /* an error occurred in the type system, we return NULL to raise
-               an exception. the typecast code should already have set the
-               exception type and text */
-            Py_DECREF(res);
-            res = NULL;
-            break;
+            err = PySequence_SetItem(res, i, val);
+            Py_DECREF(val);
+            if (err == -1) { goto exit; }
         }
     }
-    return res;
+
+    rv = 0;
+
+exit:
+    return rv;
 }
 
 static PyObject *
 _psyco_curs_buildrow(cursorObject *self, int row)
 {
     int n;
+    int istuple;
+    PyObject *t = NULL;
+    PyObject *rv = NULL;
 
     n = PQnfields(self->pgres);
-    return _psyco_curs_buildrow_fill(self, PyTuple_New(n), row, n, 1);
-}
+    istuple = (self->tuple_factory == Py_None);
 
-static PyObject *
-_psyco_curs_buildrow_with_factory(cursorObject *self, int row)
-{
-    int n;
-    PyObject *res;
+    if (istuple) {
+        t = PyTuple_New(n);
+    }
+    else {
+        t = PyObject_CallFunctionObjArgs(self->tuple_factory, self, NULL);
+    }
+    if (!t) { goto exit; }
 
-    n = PQnfields(self->pgres);
-    if (!(res = PyObject_CallFunctionObjArgs(self->tuple_factory, self, NULL)))
-        return NULL;
+    if (0 <= _psyco_curs_buildrow_fill(self, t, row, n, istuple)) {
+        rv = t;
+        t = NULL;
+    }
+
+exit:
+    Py_XDECREF(t);
+    return rv;
 
-    return _psyco_curs_buildrow_fill(self, res, row, n, 0);
 }
 
 static PyObject *
@@ -770,11 +770,7 @@ psyco_curs_fetchone(cursorObject *self, PyObject *args)
         return Py_None;
     }
 
-    if (self->tuple_factory == Py_None)
-        res = _psyco_curs_buildrow(self, self->row);
-    else
-        res = _psyco_curs_buildrow_with_factory(self, self->row);
-
+    res = _psyco_curs_buildrow(self, self->row);
     self->row++; /* move the counter to next line */
 
     /* if the query was async aggresively free pgres, to allow
@@ -821,11 +817,7 @@ psyco_curs_next_named(cursorObject *self)
         return NULL;
     }
 
-    if (self->tuple_factory == Py_None)
-        res = _psyco_curs_buildrow(self, self->row);
-    else
-        res = _psyco_curs_buildrow_with_factory(self, self->row);
-
+    res = _psyco_curs_buildrow(self, self->row);
     self->row++; /* move the counter to next line */
 
     /* if the query was async aggresively free pgres, to allow
@@ -852,7 +844,9 @@ static PyObject *
 psyco_curs_fetchmany(cursorObject *self, PyObject *args, PyObject *kwords)
 {
     int i;
-    PyObject *list, *res;
+    PyObject *list = NULL;
+    PyObject *row = NULL;
+    PyObject *rv = NULL;
 
     PyObject *pysize = NULL;
     long int size = self->arraysize;
@@ -883,8 +877,8 @@ psyco_curs_fetchmany(cursorObject *self, PyObject *args, PyObject *kwords)
         EXC_IF_TPC_PREPARED(self->conn, fetchone);
         PyOS_snprintf(buffer, 127, "FETCH FORWARD %d FROM \"%s\"",
             (int)size, self->name);
-        if (pq_execute(self, buffer, 0) == -1) return NULL;
-        if (_psyco_curs_prefetch(self) < 0) return NULL;
+        if (pq_execute(self, buffer, 0) == -1) { goto exit; }
+        if (_psyco_curs_prefetch(self) < 0) { goto exit; }
     }
 
     /* make sure size is not > than the available number of rows */
@@ -895,26 +889,21 @@ psyco_curs_fetchmany(cursorObject *self, PyObject *args, PyObject *kwords)
     Dprintf("psyco_curs_fetchmany: size = %ld", size);
 
     if (size <= 0) {
-        return PyList_New(0);
+        rv = PyList_New(0);
+        goto exit;
     }
 
-    list = PyList_New(size);
+    if (!(list = PyList_New(size))) { goto exit; }
 
     for (i = 0; i < size; i++) {
-        if (self->tuple_factory == Py_None)
-            res = _psyco_curs_buildrow(self, self->row);
-        else
-            res = _psyco_curs_buildrow_with_factory(self, self->row);
-
+        row = _psyco_curs_buildrow(self, self->row);
         self->row++;
 
-        if (res == NULL) {
-            Py_DECREF(list);
-            return NULL;
-        }
+        if (row == NULL) { goto exit; }
 
-        PyList_SET_ITEM(list, i, res);
+        PyList_SET_ITEM(list, i, row);
     }
+    row = NULL;
 
     /* if the query was async aggresively free pgres, to allow
        successive requests to reallocate it */
@@ -923,7 +912,15 @@ psyco_curs_fetchmany(cursorObject *self, PyObject *args, PyObject *kwords)
         && PyWeakref_GetObject(self->conn->async_cursor) == (PyObject*)self)
         IFCLEARPGRES(self->pgres);
 
-    return list;
+    /* success */
+    rv = list;
+    list = NULL;
+
+exit:
+    Py_XDECREF(list);
+    Py_XDECREF(row);
+
+    return rv;
 }
 
 
@@ -940,7 +937,9 @@ static PyObject *
 psyco_curs_fetchall(cursorObject *self, PyObject *args)
 {
     int i, size;
-    PyObject *list, *res;
+    PyObject *list = NULL;
+    PyObject *row = NULL;
+    PyObject *rv = NULL;
 
     EXC_IF_CURS_CLOSED(self);
     if (_psyco_curs_prefetch(self) < 0) return NULL;
@@ -953,33 +952,27 @@ psyco_curs_fetchall(cursorObject *self, PyObject *args)
         EXC_IF_ASYNC_IN_PROGRESS(self, fetchall);
         EXC_IF_TPC_PREPARED(self->conn, fetchall);
         PyOS_snprintf(buffer, 127, "FETCH FORWARD ALL FROM \"%s\"", self->name);
-        if (pq_execute(self, buffer, 0) == -1) return NULL;
-        if (_psyco_curs_prefetch(self) < 0) return NULL;
+        if (pq_execute(self, buffer, 0) == -1) { goto exit; }
+        if (_psyco_curs_prefetch(self) < 0) { goto exit; }
     }
 
     size = self->rowcount - self->row;
 
     if (size <= 0) {
-        return PyList_New(0);
+        rv = PyList_New(0);
+        goto exit;
     }
 
-    list = PyList_New(size);
+    if (!(list = PyList_New(size))) { goto exit; }
 
     for (i = 0; i < size; i++) {
-        if (self->tuple_factory == Py_None)
-            res = _psyco_curs_buildrow(self, self->row);
-        else
-            res = _psyco_curs_buildrow_with_factory(self, self->row);
-
+        row = _psyco_curs_buildrow(self, self->row);
         self->row++;
+        if (row == NULL) { goto exit; }
 
-        if (res == NULL) {
-            Py_DECREF(list);
-            return NULL;
-        }
-
-        PyList_SET_ITEM(list, i, res);
+        PyList_SET_ITEM(list, i, row);
     }
+    row = NULL;
 
     /* if the query was async aggresively free pgres, to allow
        successive requests to reallocate it */
@@ -988,7 +981,15 @@ psyco_curs_fetchall(cursorObject *self, PyObject *args)
         && PyWeakref_GetObject(self->conn->async_cursor) == (PyObject*)self)
         IFCLEARPGRES(self->pgres);
 
-    return list;
+    /* success */
+    rv = list;
+    list = NULL;
+
+exit:
+    Py_XDECREF(list);
+    Py_XDECREF(row);
+
+    return rv;
 }
 
 
@@ -998,7 +999,7 @@ psyco_curs_fetchall(cursorObject *self, PyObject *args)
 "callproc(procname, parameters=None) -- Execute stored procedure."
 
 static PyObject *
-psyco_curs_callproc(cursorObject *self, PyObject *args, PyObject *kwargs)
+psyco_curs_callproc(cursorObject *self, PyObject *args)
 {
     const char *procname = NULL;
     char *sql = NULL;
@@ -1010,7 +1011,7 @@ psyco_curs_callproc(cursorObject *self, PyObject *args, PyObject *kwargs)
     if (!PyArg_ParseTuple(args, "s#|O",
           &procname, &procname_len, &parameters
        ))
-    { return NULL; }
+    { goto exit; }
 
     EXC_IF_CURS_CLOSED(self);
     EXC_IF_ASYNC_IN_PROGRESS(self, callproc);
@@ -1019,10 +1020,10 @@ psyco_curs_callproc(cursorObject *self, PyObject *args, PyObject *kwargs)
     if (self->name != NULL) {
         psyco_set_error(ProgrammingError, self,
                          "can't call .callproc() on named cursors", NULL, NULL);
-        return NULL;
+        goto exit;
     }
 
-    if(parameters != Py_None) {
+    if (parameters != Py_None) {
         nparameters = PyObject_Length(parameters);
         if (nparameters < 0) nparameters = 0;
     }
@@ -1031,7 +1032,8 @@ psyco_curs_callproc(cursorObject *self, PyObject *args, PyObject *kwargs)
     sl = procname_len + 17 + nparameters*3 - (nparameters ? 1 : 0);
     sql = (char*)PyMem_Malloc(sl);
     if (sql == NULL) {
-        return PyErr_NoMemory();
+        PyErr_NoMemory();
+        goto exit;
     }
 
     sprintf(sql, "SELECT * FROM %s(", procname);
@@ -1041,15 +1043,16 @@ psyco_curs_callproc(cursorObject *self, PyObject *args, PyObject *kwargs)
     sql[sl-2] = ')';
     sql[sl-1] = '\0';
 
-    operation = Bytes_FromString(sql);
-    PyMem_Free((void*)sql);
+    if (!(operation = Bytes_FromString(sql))) { goto exit; }
 
-    if (_psyco_curs_execute(self, operation, parameters, self->conn->async)) {
+    if (0 <= _psyco_curs_execute(self, operation, parameters, self->conn->async)) {
         Py_INCREF(parameters);
         res = parameters;
     }
 
-    Py_DECREF(operation);
+exit:
+    Py_XDECREF(operation);
+    PyMem_Free((void*)sql);
     return res;
 }
 
@@ -1206,6 +1209,7 @@ static char *_psyco_curs_copy_columns(PyObject *columns)
     }
 
     if (NULL == (columnlist = PyMem_Malloc(bufsize))) {
+        Py_DECREF(coliter);
         PyErr_NoMemory();
         goto error;
     }
@@ -1262,8 +1266,8 @@ exit:
 #define psyco_curs_copy_from_doc \
 "copy_from(file, table, sep='\\t', null='\\\\N', size=8192, columns=None) -- Copy table from file."
 
-static int
-_psyco_curs_has_read_check(PyObject* o, void* var)
+STEALS(1) static int
+_psyco_curs_has_read_check(PyObject *o, PyObject **var)
 {
     if (PyObject_HasAttrString(o, "readline")
         && PyObject_HasAttrString(o, "read")) {
@@ -1273,7 +1277,7 @@ _psyco_curs_has_read_check(PyObject* o, void* var)
          * which could invoke the garbage collector.  We thus need an
          * INCREF/DECREF pair if we store this pointer in a GC object, such as
          * a cursorObject */
-        *((PyObject**)var) = o;
+        *var = o;
         return 1;
     }
     else {
@@ -1348,7 +1352,7 @@ psyco_curs_copy_from(cursorObject *self, PyObject *args, PyObject *kwargs)
     Py_INCREF(file);
     self->copyfile = file;
 
-    if (pq_execute(self, query, 0) == 1) {
+    if (pq_execute(self, query, 0) >= 0) {
         res = Py_None;
         Py_INCREF(Py_None);
     }
@@ -1369,11 +1373,11 @@ exit:
 #define psyco_curs_copy_to_doc \
 "copy_to(file, table, sep='\\t', null='\\\\N', columns=None) -- Copy table to file."
 
-static int
-_psyco_curs_has_write_check(PyObject* o, void* var)
+STEALS(1) static int
+_psyco_curs_has_write_check(PyObject *o, PyObject **var)
 {
     if (PyObject_HasAttrString(o, "write")) {
-        *((PyObject**)var) = o;
+        *var = o;
         return 1;
     }
     else {
@@ -1444,7 +1448,7 @@ psyco_curs_copy_to(cursorObject *self, PyObject *args, PyObject *kwargs)
     Py_INCREF(file);
     self->copyfile = file;
 
-    if (pq_execute(self, query, 0) == 1) {
+    if (pq_execute(self, query, 0) >= 0) {
         res = Py_None;
         Py_INCREF(Py_None);
     }
@@ -1518,7 +1522,7 @@ psyco_curs_copy_expert(cursorObject *self, PyObject *args, PyObject *kwargs)
     self->copyfile = file;
 
     /* At this point, the SQL statement must be str, not unicode */
-    if (pq_execute(self, Bytes_AS_STRING(sql), 0) == 1) {
+    if (pq_execute(self, Bytes_AS_STRING(sql), 0) >= 0) {
         res = Py_None;
         Py_INCREF(res);
     }
diff --git a/psycopg/lobject.h b/psycopg/lobject.h
index f52d85cf..6587198c 100644
--- a/psycopg/lobject.h
+++ b/psycopg/lobject.h
@@ -51,19 +51,19 @@ typedef struct {
 
 /* functions exported from lobject_int.c */
 
-HIDDEN int lobject_open(lobjectObject *self, connectionObject *conn,
-                        Oid oid, const char *smode, Oid new_oid,
-                        const char *new_file);
-HIDDEN int lobject_unlink(lobjectObject *self);
-HIDDEN int lobject_export(lobjectObject *self, const char *filename);
+RAISES_NEG HIDDEN int lobject_open(lobjectObject *self, connectionObject *conn,
+                                   Oid oid, const char *smode, Oid new_oid,
+                                   const char *new_file);
+RAISES_NEG HIDDEN int lobject_unlink(lobjectObject *self);
+RAISES_NEG HIDDEN int lobject_export(lobjectObject *self, const char *filename);
 
-HIDDEN Py_ssize_t lobject_read(lobjectObject *self, char *buf, size_t len);
-HIDDEN Py_ssize_t lobject_write(lobjectObject *self, const char *buf,
+RAISES_NEG HIDDEN Py_ssize_t lobject_read(lobjectObject *self, char *buf, size_t len);
+RAISES_NEG HIDDEN Py_ssize_t lobject_write(lobjectObject *self, const char *buf,
                                 size_t len);
-HIDDEN int lobject_seek(lobjectObject *self, int pos, int whence);
-HIDDEN int lobject_tell(lobjectObject *self);
-HIDDEN int lobject_truncate(lobjectObject *self, size_t len);
-HIDDEN int lobject_close(lobjectObject *self);
+RAISES_NEG HIDDEN int lobject_seek(lobjectObject *self, int pos, int whence);
+RAISES_NEG HIDDEN int lobject_tell(lobjectObject *self);
+RAISES_NEG HIDDEN int lobject_truncate(lobjectObject *self, size_t len);
+RAISES_NEG HIDDEN int lobject_close(lobjectObject *self);
 
 #define lobject_is_closed(self) \
     ((self)->fd < 0 || !(self)->conn || (self)->conn->closed)
diff --git a/psycopg/lobject_int.c b/psycopg/lobject_int.c
index f180c8c2..5f23ca25 100644
--- a/psycopg/lobject_int.c
+++ b/psycopg/lobject_int.c
@@ -50,7 +50,7 @@ collect_error(connectionObject *conn, char **error)
  *
  * Valid mode are [r|w|rw|n][t|b]
  */
-static int
+RAISES_NEG static int
 _lobject_parse_mode(const char *mode)
 {
     int rv = 0;
@@ -147,7 +147,7 @@ _lobject_unparse_mode(int mode)
 
 /* lobject_open - create a new/open an existing lo */
 
-int
+RAISES_NEG int
 lobject_open(lobjectObject *self, connectionObject *conn,
               Oid oid, const char *smode, Oid new_oid, const char *new_file)
 {
@@ -237,7 +237,7 @@ lobject_open(lobjectObject *self, connectionObject *conn,
 
 /* lobject_close - close an existing lo */
 
-static int
+RAISES_NEG static int
 lobject_close_locked(lobjectObject *self, char **error)
 {
     int retvalue;
@@ -270,7 +270,7 @@ lobject_close_locked(lobjectObject *self, char **error)
     return retvalue;
 }
 
-int
+RAISES_NEG int
 lobject_close(lobjectObject *self)
 {
     PGresult *pgres = NULL;
@@ -292,7 +292,7 @@ lobject_close(lobjectObject *self)
 
 /* lobject_unlink - remove an lo from database */
 
-int
+RAISES_NEG int
 lobject_unlink(lobjectObject *self)
 {
     PGresult *pgres = NULL;
@@ -326,7 +326,7 @@ lobject_unlink(lobjectObject *self)
 
 /* lobject_write - write bytes to a lo */
 
-Py_ssize_t
+RAISES_NEG Py_ssize_t
 lobject_write(lobjectObject *self, const char *buf, size_t len)
 {
     Py_ssize_t written;
@@ -353,7 +353,7 @@ lobject_write(lobjectObject *self, const char *buf, size_t len)
 
 /* lobject_read - read bytes from a lo */
 
-Py_ssize_t
+RAISES_NEG Py_ssize_t
 lobject_read(lobjectObject *self, char *buf, size_t len)
 {
     Py_ssize_t n_read;
@@ -377,7 +377,7 @@ lobject_read(lobjectObject *self, char *buf, size_t len)
 
 /* lobject_seek - move the current position in the lo */
 
-int
+RAISES_NEG int
 lobject_seek(lobjectObject *self, int pos, int whence)
 {
     PGresult *pgres = NULL;
@@ -405,7 +405,7 @@ lobject_seek(lobjectObject *self, int pos, int whence)
 
 /* lobject_tell - tell the current position in the lo */
 
-int
+RAISES_NEG int
 lobject_tell(lobjectObject *self)
 {
     PGresult *pgres = NULL;
@@ -432,7 +432,7 @@ lobject_tell(lobjectObject *self)
 
 /* lobject_export - export to a local file */
 
-int
+RAISES_NEG int
 lobject_export(lobjectObject *self, const char *filename)
 {
     PGresult *pgres = NULL;
@@ -461,7 +461,7 @@ lobject_export(lobjectObject *self, const char *filename)
 
 #if PG_VERSION_HEX >= 0x080300
 
-int
+RAISES_NEG int
 lobject_truncate(lobjectObject *self, size_t len)
 {
     int retvalue;
diff --git a/psycopg/lobject_type.c b/psycopg/lobject_type.c
index a55272ca..625a2939 100644
--- a/psycopg/lobject_type.c
+++ b/psycopg/lobject_type.c
@@ -373,7 +373,7 @@ lobject_dealloc(PyObject* obj)
 static int
 lobject_init(PyObject *obj, PyObject *args, PyObject *kwds)
 {
-    Oid oid=InvalidOid, new_oid=InvalidOid;
+    int oid = (int)InvalidOid, new_oid = (int)InvalidOid;
     const char *smode = "";
     const char *new_file = NULL;
     PyObject *conn;
@@ -383,7 +383,7 @@ lobject_init(PyObject *obj, PyObject *args, PyObject *kwds)
         return -1;
 
     return lobject_setup((lobjectObject *)obj,
-        (connectionObject *)conn, oid, smode, new_oid, new_file);
+        (connectionObject *)conn, (Oid)oid, smode, (Oid)new_oid, new_file);
 }
 
 static PyObject *
diff --git a/psycopg/microprotocols.c b/psycopg/microprotocols.c
index f48c0fbf..23f12794 100644
--- a/psycopg/microprotocols.c
+++ b/psycopg/microprotocols.c
@@ -52,29 +52,35 @@ microprotocols_init(PyObject *dict)
 }
 
 
-/* microprotocols_add - add a reverse type-caster to the dictionary */
-
+/* microprotocols_add - add a reverse type-caster to the dictionary
+ *
+ * Return 0 on success, else -1 and set an exception.
+ */
 int
 microprotocols_add(PyTypeObject *type, PyObject *proto, PyObject *cast)
 {
-    PyObject *key;
+    PyObject *key = NULL;
+    int rv = -1;
 
     if (proto == NULL) proto = (PyObject*)&isqlquoteType;
 
     Dprintf("microprotocols_add: cast %p for (%s, ?)", cast, type->tp_name);
 
-    key = PyTuple_Pack(2, (PyObject*)type, proto);
-    PyDict_SetItem(psyco_adapters, key, cast);
-    Py_DECREF(key);
+    if (!(key = PyTuple_Pack(2, (PyObject*)type, proto))) { goto exit; }
+    if (0 != PyDict_SetItem(psyco_adapters, key, cast)) { goto exit; }
 
-    return 0;
+    rv = 0;
+
+exit:
+    Py_XDECREF(key);
+    return rv;
 }
 
 /* Check if one of `obj` superclasses has an adapter for `proto`.
  *
- * If it does, return a *borrowed reference* to the adapter, else NULL.
+ * If it does, return a *borrowed reference* to the adapter, else to None.
  */
-static PyObject *
+BORROWED static PyObject *
 _get_superclass_adapter(PyObject *obj, PyObject *proto)
 {
     PyTypeObject *type;
@@ -89,14 +95,14 @@ _get_superclass_adapter(PyObject *obj, PyObject *proto)
 #endif
         type->tp_mro)) {
         /* has no mro */
-        return NULL;
+        return Py_None;
     }
 
     /* Walk the mro from the most specific subclass. */
     mro = type->tp_mro;
     for (i = 1, ii = PyTuple_GET_SIZE(mro); i < ii; ++i) {
         st = PyTuple_GET_ITEM(mro, i);
-        key = PyTuple_Pack(2, st, proto);
+        if (!(key = PyTuple_Pack(2, st, proto))) { return NULL; }
         adapter = PyDict_GetItem(psyco_adapters, key);
         Py_DECREF(key);
 
@@ -119,7 +125,7 @@ _get_superclass_adapter(PyObject *obj, PyObject *proto)
             return adapter;
         }
     }
-    return NULL;
+    return Py_None;
 }
 
 
@@ -139,7 +145,7 @@ microprotocols_adapt(PyObject *obj, PyObject *proto, PyObject *alt)
         Py_TYPE(obj)->tp_name);
 
     /* look for an adapter in the registry */
-    key = PyTuple_Pack(2, Py_TYPE(obj), proto);
+    if (!(key = PyTuple_Pack(2, Py_TYPE(obj), proto))) { return NULL; }
     adapter = PyDict_GetItem(psyco_adapters, key);
     Py_DECREF(key);
     if (adapter) {
@@ -148,7 +154,10 @@ microprotocols_adapt(PyObject *obj, PyObject *proto, PyObject *alt)
     }
 
     /* Check if a superclass can be adapted and use the same adapter. */
-    if (NULL != (adapter = _get_superclass_adapter(obj, proto))) {
+    if (!(adapter = _get_superclass_adapter(obj, proto))) {
+        return NULL;
+    }
+    if (Py_None != adapter) {
         adapted = PyObject_CallFunctionObjArgs(adapter, obj, NULL);
         return adapted;
     }
diff --git a/psycopg/pqpath.c b/psycopg/pqpath.c
index adbaa74c..6ba4eca6 100644
--- a/psycopg/pqpath.c
+++ b/psycopg/pqpath.c
@@ -64,7 +64,7 @@ strip_severity(const char *msg)
    code.  A list of error codes can be found at:
 
    http://www.postgresql.org/docs/current/static/errcodes-appendix.html */
-static PyObject *
+BORROWED static PyObject *
 exception_from_sqlstate(const char *sqlstate)
 {
     switch (sqlstate[0]) {
@@ -151,7 +151,7 @@ exception_from_sqlstate(const char *sqlstate)
 
    This function should be called while holding the GIL. */
 
-static void
+RAISES static void
 pq_raise(connectionObject *conn, cursorObject *curs, PGresult *pgres)
 {
     PyObject *exc = NULL;
@@ -164,7 +164,7 @@ pq_raise(connectionObject *conn, cursorObject *curs, PGresult *pgres)
             "psycopg went psycotic and raised a null error");
         return;
     }
-    
+
     /* if the connection has somehow beed broken, we mark the connection
        object as closed but requiring cleanup */
     if (conn->pgconn != NULL && PQstatus(conn->pgconn) == CONNECTION_BAD)
@@ -249,7 +249,9 @@ pq_clear_critical(connectionObject *conn)
     }
 }
 
-static PyObject *
+/* return -1 if the exception is set (i.e. if conn->critical is set),
+ * else 0 */
+RAISES_NEG static int
 pq_resolve_critical(connectionObject *conn, int close)
 {
     Dprintf("pq_resolve_critical: resolving %s", conn->critical);
@@ -264,11 +266,13 @@ pq_resolve_critical(connectionObject *conn, int close)
 
         /* we don't want to destroy this connection but just close it */
         if (close == 1) conn_close(conn);
-    
+
         /* remember to clear the critical! */
-        pq_clear_critical(conn);    
+        pq_clear_critical(conn);
+
+        return -1;
     }
-    return NULL;
+    return 0;
 }
 
 /* pq_clear_async - clear the effects of a previous async query
@@ -300,19 +304,16 @@ pq_clear_async(connectionObject *conn)
 
    Accepted arg values are 1 (nonblocking) and 0 (blocking).
 
-   Return 0 if everything ok, else nonzero.
-
-   In case of error, if pyerr is nonzero, set a Python exception.
+   Return 0 if everything ok, else < 0 and set an exception.
  */
-int
-pq_set_non_blocking(connectionObject *conn, int arg, int pyerr)
+RAISES_NEG int
+pq_set_non_blocking(connectionObject *conn, int arg)
 {
     int ret = PQsetnonblocking(conn->pgconn, arg);
     if (0 != ret) {
         Dprintf("PQsetnonblocking(%d) FAILED", arg);
-        if (pyerr) {
-            PyErr_SetString(OperationalError, "PQsetnonblocking() failed");
-        }
+        PyErr_SetString(OperationalError, "PQsetnonblocking() failed");
+        ret = -1;
     }
     return ret;
 }
@@ -382,7 +383,7 @@ cleanup:
    This function should be called while holding the global interpreter
    lock.
  */
-void
+RAISES void
 pq_complete_error(connectionObject *conn, PGresult **pgres, char **error)
 {
     Dprintf("pq_complete_error: pgconn = %p, pgres = %p, error = %s",
@@ -476,7 +477,7 @@ pq_commit(connectionObject *conn)
     return retvalue;
 }
 
-int
+RAISES_NEG int
 pq_abort_locked(connectionObject *conn, PGresult **pgres, char **error,
                 PyThreadState **tstate)
 {
@@ -503,7 +504,7 @@ pq_abort_locked(connectionObject *conn, PGresult **pgres, char **error,
    This function should be called while holding the global interpreter
    lock. */
 
-int
+RAISES_NEG int
 pq_abort(connectionObject *conn)
 {
     int retvalue = -1;
@@ -540,7 +541,7 @@ pq_abort(connectionObject *conn)
    connection without holding the global interpreter lock.
 */
 
-int
+RAISES_NEG int
 pq_reset_locked(connectionObject *conn, PGresult **pgres, char **error,
                 PyThreadState **tstate)
 {
@@ -832,7 +833,7 @@ pq_flush(connectionObject *conn)
    this fucntion locks the connection object
    this function call Py_*_ALLOW_THREADS macros */
 
-int
+RAISES_NEG int
 pq_execute(cursorObject *curs, const char *query, int async)
 {
     PGresult *pgres = NULL;
@@ -842,8 +843,7 @@ pq_execute(cursorObject *curs, const char *query, int async)
     /* if the status of the connection is critical raise an exception and
        definitely close the connection */
     if (curs->conn->critical) {
-        pq_resolve_critical(curs->conn, 1);
-        return -1;
+        return pq_resolve_critical(curs->conn, 1);
     }
 
     /* check status of connection, raise error if not OK */
@@ -938,12 +938,13 @@ pq_execute(cursorObject *curs, const char *query, int async)
        to respect the old DBAPI-2.0 compatible behaviour */
     if (async == 0) {
         Dprintf("pq_execute: entering syncronous DBAPI compatibility mode");
-        if (pq_fetch(curs) == -1) return -1;
+        if (pq_fetch(curs) < 0) return -1;
     }
     else {
+        PyObject *tmp;
         curs->conn->async_status = async_status;
-        curs->conn->async_cursor = PyWeakref_NewRef((PyObject *)curs, NULL);
-        if (!curs->conn->async_cursor) {
+        curs->conn->async_cursor = tmp = PyWeakref_NewRef((PyObject *)curs, NULL);
+        if (!tmp) {
             /* weakref creation failed */
             return -1;
         }
@@ -1012,7 +1013,7 @@ pq_get_last_result(connectionObject *conn)
       1 - result from backend (possibly data is ready)
 */
 
-static int
+RAISES_NEG static int
 _pq_fetch_tuples(cursorObject *curs)
 {
     int i, *dsize = NULL;
@@ -1412,8 +1413,7 @@ pq_fetch(cursorObject *curs)
         Dprintf("pq_fetch: got a NULL pgres, checking for critical");
         pq_set_critical(curs->conn);
         if (curs->conn->critical) {
-            pq_resolve_critical(curs->conn);
-            return -1;
+            return pq_resolve_critical(curs->conn);
         }
         else {
             return 0;
@@ -1489,13 +1489,7 @@ pq_fetch(cursorObject *curs)
        raise the exception but we avoid to close the connection) */
     Dprintf("pq_fetch: fetching done; check for critical errors");
     if (curs->conn->critical) {
-        if (ex == -1) {
-            pq_resolve_critical(curs->conn, 1);
-        }
-        else {
-            pq_resolve_critical(curs->conn, 0);
-        }
-        return -1;
+        return pq_resolve_critical(curs->conn, ex == -1 ? 1 : 0);
     }
 
     return ex;
diff --git a/psycopg/pqpath.h b/psycopg/pqpath.h
index bf012ade..a8f39c18 100644
--- a/psycopg/pqpath.h
+++ b/psycopg/pqpath.h
@@ -35,18 +35,18 @@
 
 /* exported functions */
 HIDDEN PGresult *pq_get_last_result(connectionObject *conn);
-HIDDEN int pq_fetch(cursorObject *curs);
-HIDDEN int pq_execute(cursorObject *curs, const char *query, int async);
+RAISES_NEG HIDDEN int pq_fetch(cursorObject *curs);
+RAISES_NEG HIDDEN int pq_execute(cursorObject *curs, const char *query, int async);
 HIDDEN int pq_send_query(connectionObject *conn, const char *query);
 HIDDEN int pq_begin_locked(connectionObject *conn, PGresult **pgres,
                            char **error, PyThreadState **tstate);
 HIDDEN int pq_commit(connectionObject *conn);
-HIDDEN int pq_abort_locked(connectionObject *conn, PGresult **pgres,
+RAISES_NEG HIDDEN int pq_abort_locked(connectionObject *conn, PGresult **pgres,
                            char **error, PyThreadState **tstate);
-HIDDEN int pq_abort(connectionObject *conn);
+RAISES_NEG HIDDEN int pq_abort(connectionObject *conn);
 HIDDEN int pq_reset_locked(connectionObject *conn, PGresult **pgres,
                             char **error, PyThreadState **tstate);
-HIDDEN int pq_reset(connectionObject *conn);
+RAISES_NEG HIDDEN int pq_reset(connectionObject *conn);
 HIDDEN char *pq_get_guc_locked(connectionObject *conn, const char *param,
                                PGresult **pgres,
                                char **error, PyThreadState **tstate);
@@ -61,7 +61,7 @@ HIDDEN int pq_is_busy(connectionObject *conn);
 HIDDEN int pq_is_busy_locked(connectionObject *conn);
 HIDDEN int pq_flush(connectionObject *conn);
 HIDDEN void pq_clear_async(connectionObject *conn);
-HIDDEN int pq_set_non_blocking(connectionObject *conn, int arg, int pyerr);
+RAISES_NEG HIDDEN int pq_set_non_blocking(connectionObject *conn, int arg);
 
 HIDDEN void pq_set_critical(connectionObject *conn, const char *msg);
 
@@ -69,7 +69,7 @@ HIDDEN int pq_execute_command_locked(connectionObject *conn,
                                      const char *query,
                                      PGresult **pgres, char **error,
                                      PyThreadState **tstate);
-HIDDEN void pq_complete_error(connectionObject *conn, PGresult **pgres,
+RAISES HIDDEN void pq_complete_error(connectionObject *conn, PGresult **pgres,
                               char **error);
 
 #endif /* !defined(PSYCOPG_PQPATH_H) */
diff --git a/psycopg/psycopg.h b/psycopg/psycopg.h
index 2f06c378..2e86dca8 100644
--- a/psycopg/psycopg.h
+++ b/psycopg/psycopg.h
@@ -120,17 +120,19 @@ HIDDEN PyObject *psyco_GetDecimalType(void);
 typedef struct cursorObject cursorObject;
 
 /* some utility functions */
-HIDDEN void psyco_set_error(PyObject *exc, cursorObject *curs, const char *msg,
+RAISES HIDDEN void psyco_set_error(PyObject *exc, cursorObject *curs, const char *msg,
                             const char *pgerror, const char *pgcode);
 
 HIDDEN char *psycopg_escape_string(PyObject *conn,
               const char *from, Py_ssize_t len, char *to, Py_ssize_t *tolen);
 HIDDEN char *psycopg_escape_identifier_easy(const char *from, Py_ssize_t len);
-HIDDEN char *psycopg_strdup(const char *from, Py_ssize_t len);
-HIDDEN PyObject * psycopg_ensure_bytes(PyObject *obj);
-HIDDEN PyObject * psycopg_ensure_text(PyObject *obj);
+HIDDEN int psycopg_strdup(char **to, const char *from, Py_ssize_t len);
 HIDDEN int psycopg_is_text_file(PyObject *f);
 
+STEALS(1) HIDDEN PyObject * psycopg_ensure_bytes(PyObject *obj);
+
+STEALS(1) HIDDEN PyObject * psycopg_ensure_text(PyObject *obj);
+
 /* Exceptions docstrings */
 #define Error_doc \
 "Base class for error exceptions."
diff --git a/psycopg/psycopgmodule.c b/psycopg/psycopgmodule.c
index 438b018e..3328c609 100644
--- a/psycopg/psycopgmodule.c
+++ b/psycopg/psycopgmodule.c
@@ -143,14 +143,6 @@ psyco_connect(PyObject *self, PyObject *args, PyObject *keywds)
 "  * `name`: Name for the new type\n" \
 "  * `baseobj`: Adapter to perform type conversion of a single array item."
 
-static void
-_psyco_register_type_set(PyObject **dict, PyObject *type)
-{
-    if (*dict == NULL)
-        *dict = PyDict_New();
-    typecast_add(type, *dict, 0);
-}
-
 static PyObject *
 psyco_register_type(PyObject *self, PyObject *args)
 {
@@ -162,10 +154,16 @@ psyco_register_type(PyObject *self, PyObject *args)
 
     if (obj != NULL && obj != Py_None) {
         if (PyObject_TypeCheck(obj, &cursorType)) {
-            _psyco_register_type_set(&(((cursorObject*)obj)->string_types), type);
+            PyObject **dict = &(((cursorObject*)obj)->string_types);
+            if (*dict == NULL) {
+                if (!(*dict = PyDict_New())) { return NULL; }
+            }
+            if (0 > typecast_add(type, *dict, 0)) { return NULL; }
         }
         else if (PyObject_TypeCheck(obj, &connectionType)) {
-            typecast_add(type, ((connectionObject*)obj)->string_types, 0);
+            if (0 > typecast_add(type, ((connectionObject*)obj)->string_types, 0)) {
+                return NULL;
+            }
         }
         else {
             PyErr_SetString(PyExc_TypeError,
@@ -174,7 +172,7 @@ psyco_register_type(PyObject *self, PyObject *args)
         }
     }
     else {
-        typecast_add(type, NULL, 0);
+        if (0 > typecast_add(type, NULL, 0)) { return NULL; }
     }
 
     Py_INCREF(Py_None);
@@ -182,66 +180,108 @@ psyco_register_type(PyObject *self, PyObject *args)
 }
 
 
-/* default adapters */
-
-static void
+/* Initialize the default adapters map
+ *
+ * Return 0 on success, else -1 and set an exception.
+ */
+static int
 psyco_adapters_init(PyObject *mod)
 {
-    PyObject *call;
+    PyObject *call = NULL;
+    int rv = -1;
 
-    microprotocols_add(&PyFloat_Type, NULL, (PyObject*)&pfloatType);
+    if (0 != microprotocols_add(&PyFloat_Type, NULL, (PyObject*)&pfloatType)) {
+        goto exit;
+    }
 #if PY_MAJOR_VERSION < 3
-    microprotocols_add(&PyInt_Type, NULL, (PyObject*)&pintType);
+    if (0 != microprotocols_add(&PyInt_Type, NULL, (PyObject*)&pintType)) {
+        goto exit;
+    }
 #endif
-    microprotocols_add(&PyLong_Type, NULL, (PyObject*)&pintType);
-    microprotocols_add(&PyBool_Type, NULL, (PyObject*)&pbooleanType);
+    if (0 != microprotocols_add(&PyLong_Type, NULL, (PyObject*)&pintType)) {
+        goto exit;
+    }
+    if (0 != microprotocols_add(&PyBool_Type, NULL, (PyObject*)&pbooleanType)) {
+        goto exit;
+    }
 
     /* strings */
 #if PY_MAJOR_VERSION < 3
-    microprotocols_add(&PyString_Type, NULL, (PyObject*)&qstringType);
+    if (0 != microprotocols_add(&PyString_Type, NULL, (PyObject*)&qstringType)) {
+        goto exit;
+    }
 #endif
-    microprotocols_add(&PyUnicode_Type, NULL, (PyObject*)&qstringType);
+    if (0 != microprotocols_add(&PyUnicode_Type, NULL, (PyObject*)&qstringType)) {
+        goto exit;
+    }
 
     /* binary */
 #if PY_MAJOR_VERSION < 3
-    microprotocols_add(&PyBuffer_Type, NULL, (PyObject*)&binaryType);
+    if (0 != microprotocols_add(&PyBuffer_Type, NULL, (PyObject*)&binaryType)) {
+        goto exit;
+    }
 #else
-    microprotocols_add(&PyBytes_Type, NULL, (PyObject*)&binaryType);
+    if (0 != microprotocols_add(&PyBytes_Type, NULL, (PyObject*)&binaryType)) {
+        goto exit;
+    }
 #endif
 
 #if PY_MAJOR_VERSION >= 3 || PY_MINOR_VERSION >= 6
-    microprotocols_add(&PyByteArray_Type, NULL, (PyObject*)&binaryType);
+    if (0 != microprotocols_add(&PyByteArray_Type, NULL, (PyObject*)&binaryType)) {
+        goto exit;
+    }
 #endif
 #if PY_MAJOR_VERSION >= 3 || PY_MINOR_VERSION >= 7
-    microprotocols_add(&PyMemoryView_Type, NULL, (PyObject*)&binaryType);
+    if (0 != microprotocols_add(&PyMemoryView_Type, NULL, (PyObject*)&binaryType)) {
+        goto exit;
+    }
 #endif
 
-    microprotocols_add(&PyList_Type, NULL, (PyObject*)&listType);
+    if (0 != microprotocols_add(&PyList_Type, NULL, (PyObject*)&listType)) {
+        goto exit;
+    }
 
     /* the module has already been initialized, so we can obtain the callable
        objects directly from its dictionary :) */
-    call = PyMapping_GetItemString(mod, "DateFromPy");
-    microprotocols_add(PyDateTimeAPI->DateType, NULL, call);
-    call = PyMapping_GetItemString(mod, "TimeFromPy");
-    microprotocols_add(PyDateTimeAPI->TimeType, NULL, call);
-    call = PyMapping_GetItemString(mod, "TimestampFromPy");
-    microprotocols_add(PyDateTimeAPI->DateTimeType, NULL, call);
-    call = PyMapping_GetItemString(mod, "IntervalFromPy");
-    microprotocols_add(PyDateTimeAPI->DeltaType, NULL, call);
+    if (!(call = PyMapping_GetItemString(mod, "DateFromPy"))) { goto exit; }
+    if (0 != microprotocols_add(PyDateTimeAPI->DateType, NULL, call)) { goto exit; }
+    Py_CLEAR(call);
+
+    if (!(call = PyMapping_GetItemString(mod, "TimeFromPy"))) { goto exit; }
+    if (0 != microprotocols_add(PyDateTimeAPI->TimeType, NULL, call)) { goto exit; }
+    Py_CLEAR(call);
+
+    if (!(call = PyMapping_GetItemString(mod, "TimestampFromPy"))) { goto exit; }
+    if (0 != microprotocols_add(PyDateTimeAPI->DateTimeType, NULL, call)) { goto exit; }
+    Py_CLEAR(call);
+
+    if (!(call = PyMapping_GetItemString(mod, "IntervalFromPy"))) { goto exit; }
+    if (0 != microprotocols_add(PyDateTimeAPI->DeltaType, NULL, call)) { goto exit; }
+    Py_CLEAR(call);
 
 #ifdef HAVE_MXDATETIME
     /* as above, we use the callable objects from the psycopg module */
     if (NULL != (call = PyMapping_GetItemString(mod, "TimestampFromMx"))) {
-        microprotocols_add(mxDateTime.DateTime_Type, NULL, call);
+        if (0 != microprotocols_add(mxDateTime.DateTime_Type, NULL, call)) { goto exit; }
+        Py_CLEAR(call);
 
         /* if we found the above, we have this too. */
-        call = PyMapping_GetItemString(mod, "TimeFromMx");
-        microprotocols_add(mxDateTime.DateTimeDelta_Type, NULL, call);
+        if (!(call = PyMapping_GetItemString(mod, "TimeFromMx"))) { goto exit; }
+        if (0 != microprotocols_add(mxDateTime.DateTimeDelta_Type, NULL, call)) { goto exit; }
+        Py_CLEAR(call);
     }
     else {
         PyErr_Clear();
     }
 #endif
+
+    /* Success! */
+    rv = 0;
+
+exit:
+    Py_XDECREF(call);
+
+    return rv;
 }
 
 /* psyco_encodings_fill
@@ -326,15 +366,27 @@ static encodingPair encodings[] = {
     {NULL, NULL}
 };
 
-static void psyco_encodings_fill(PyObject *dict)
+/* Initialize the encodings table.
+ *
+ * Return 0 on success, else -1 and set an exception.
+ */
+static int psyco_encodings_fill(PyObject *dict)
 {
+    PyObject *value = NULL;
     encodingPair *enc;
+    int rv = -1;
 
     for (enc = encodings; enc->pgenc != NULL; enc++) {
-        PyObject *value = Text_FromUTF8(enc->pyenc);
-        PyDict_SetItemString(dict, enc->pgenc, value);
-        Py_DECREF(value);
+        if (!(value = Text_FromUTF8(enc->pyenc))) { goto exit; }
+        if (0 != PyDict_SetItemString(dict, enc->pgenc, value)) { goto exit; }
+        Py_CLEAR(value);
     }
+    rv = 0;
+
+exit:
+    Py_XDECREF(value);
+
+    return rv;
 }
 
 /* psyco_errors_init, psyco_errors_fill (callable from C)
@@ -440,21 +492,22 @@ psyco_errors_init(void)
        live in _psycopg */
 
     int i;
-    PyObject *dict;
+    PyObject *dict = NULL;
     PyObject *base;
-    PyObject *str;
-    PyObject *descr;
+    PyObject *str = NULL;
+    PyObject *descr = NULL;
     int rv = -1;
 
     static PyMethodDef psyco_error_reduce_ex_def =
         {"__reduce_ex__", psyco_error_reduce_ex, METH_VARARGS, "pickle helper"};
 
     for (i=0; exctable[i].name; i++) {
-        dict = PyDict_New();
+        if (!(dict = PyDict_New())) { goto exit; }
 
         if (exctable[i].docstr) {
-            str = Text_FromUTF8(exctable[i].docstr);
-            PyDict_SetItemString(dict, "__doc__", str);
+            if (!(str = Text_FromUTF8(exctable[i].docstr))) { goto exit; }
+            if (0 != PyDict_SetItemString(dict, "__doc__", str)) { goto exit; }
+            Py_CLEAR(str);
         }
 
         if (exctable[i].base == 0) {
@@ -468,7 +521,11 @@ psyco_errors_init(void)
         else
             base = *exctable[i].base;
 
-        *exctable[i].exc = PyErr_NewException(exctable[i].name, base, dict);
+        if (!(*exctable[i].exc = PyErr_NewException(
+                exctable[i].name, base, dict))) {
+            goto exit;
+        }
+        Py_CLEAR(dict);
     }
 
     /* Make pgerror, pgcode and cursor default to None on psycopg
@@ -492,60 +549,56 @@ psyco_errors_init(void)
             psyco_error_reduce_ex_def.ml_name, descr)) {
         goto exit;
     }
-    Py_DECREF(descr);
 #endif
 
     rv = 0;
 
 exit:
+    Py_XDECREF(descr);
+    Py_XDECREF(str);
+    Py_XDECREF(dict);
     return rv;
 }
 
 void
 psyco_errors_fill(PyObject *dict)
 {
-    PyDict_SetItemString(dict, "Error", Error);
-    PyDict_SetItemString(dict, "Warning", Warning);
-    PyDict_SetItemString(dict, "InterfaceError", InterfaceError);
-    PyDict_SetItemString(dict, "DatabaseError", DatabaseError);
-    PyDict_SetItemString(dict, "InternalError", InternalError);
-    PyDict_SetItemString(dict, "OperationalError", OperationalError);
-    PyDict_SetItemString(dict, "ProgrammingError", ProgrammingError);
-    PyDict_SetItemString(dict, "IntegrityError", IntegrityError);
-    PyDict_SetItemString(dict, "DataError", DataError);
-    PyDict_SetItemString(dict, "NotSupportedError", NotSupportedError);
-#ifdef PSYCOPG_EXTENSIONS
-    PyDict_SetItemString(dict, "QueryCanceledError", QueryCanceledError);
-    PyDict_SetItemString(dict, "TransactionRollbackError",
-                         TransactionRollbackError);
-#endif
+    int i;
+    char *name;
+
+    for (i = 0; exctable[i].name; i++) {
+        if (NULL == exctable[i].exc) { continue; }
+
+        /* the name is the part after the last dot */
+        name = strrchr(exctable[i].name, '.');
+        name = name ? name + 1 : exctable[i].name;
+
+        PyDict_SetItemString(dict, name, *exctable[i].exc);
+    }
 }
 
 void
 psyco_errors_set(PyObject *type)
 {
-    PyObject_SetAttrString(type, "Error", Error);
-    PyObject_SetAttrString(type, "Warning", Warning);
-    PyObject_SetAttrString(type, "InterfaceError", InterfaceError);
-    PyObject_SetAttrString(type, "DatabaseError", DatabaseError);
-    PyObject_SetAttrString(type, "InternalError", InternalError);
-    PyObject_SetAttrString(type, "OperationalError", OperationalError);
-    PyObject_SetAttrString(type, "ProgrammingError", ProgrammingError);
-    PyObject_SetAttrString(type, "IntegrityError", IntegrityError);
-    PyObject_SetAttrString(type, "DataError", DataError);
-    PyObject_SetAttrString(type, "NotSupportedError", NotSupportedError);
-#ifdef PSYCOPG_EXTENSIONS
-    PyObject_SetAttrString(type, "QueryCanceledError", QueryCanceledError);
-    PyObject_SetAttrString(type, "TransactionRollbackError",
-                           TransactionRollbackError);
-#endif
+    int i;
+    char *name;
+
+    for (i = 0; exctable[i].name; i++) {
+        if (NULL == exctable[i].exc) { continue; }
+
+        /* the name is the part after the last dot */
+        name = strrchr(exctable[i].name, '.');
+        name = name ? name + 1 : exctable[i].name;
+
+        PyObject_SetAttrString(type, name, *exctable[i].exc);
+    }
 }
 
-/* psyco_error_new
+/* psyco_set_error
 
    Create a new error of the given type with extra attributes. */
 
-void
+RAISES void
 psyco_set_error(PyObject *exc, cursorObject *curs, const char *msg,
                 const char *pgerror, const char *pgcode)
 {
@@ -574,15 +627,17 @@ psyco_set_error(PyObject *exc, cursorObject *curs, const char *msg,
         }
 
         if (pgerror) {
-            t = conn_text_from_chars(conn, pgerror);
-            PyObject_SetAttrString(err, "pgerror", t);
-            Py_DECREF(t);
+            if ((t = conn_text_from_chars(conn, pgerror))) {
+                PyObject_SetAttrString(err, "pgerror", t);
+                Py_DECREF(t);
+            }
         }
 
         if (pgcode) {
-            t = conn_text_from_chars(conn, pgcode);
-            PyObject_SetAttrString(err, "pgcode", t);
-            Py_DECREF(t);
+            if ((t = conn_text_from_chars(conn, pgcode))) {
+                PyObject_SetAttrString(err, "pgcode", t);
+                Py_DECREF(t);
+            }
         }
 
         PyErr_SetObject(exc, err);
@@ -649,7 +704,7 @@ psyco_GetDecimalType(void)
     }
 
     /* Store the object from future uses. */
-    if (can_cache && !cachedType) {
+    if (can_cache && !cachedType && decimalType) {
         Py_INCREF(decimalType);
         cachedType = decimalType;
     }
@@ -673,15 +728,11 @@ psyco_make_description_type(void)
     /* Try to import collections.namedtuple */
     if (!(coll = PyImport_ImportModule("collections"))) {
         Dprintf("psyco_make_description_type: collections import failed");
-        PyErr_Clear();
-        rv = Py_None;
-        goto exit;
+        goto error;
     }
     if (!(nt = PyObject_GetAttrString(coll, "namedtuple"))) {
         Dprintf("psyco_make_description_type: no collections.namedtuple");
-        PyErr_Clear();
-        rv = Py_None;
-        goto exit;
+        goto error;
     }
 
     /* Build the namedtuple */
@@ -693,6 +744,13 @@ exit:
     Py_XDECREF(nt);
 
     return rv;
+
+error:
+    /* controlled error: we will fall back to regular tuples. Return None. */
+    PyErr_Clear();
+    rv = Py_None;
+    Py_INCREF(rv);
+    goto exit;
 }
 
 
@@ -905,10 +963,10 @@ INIT_MODULE(_psycopg)(void)
 #endif
 
     /* other mixed initializations of module-level variables */
-    psycoEncodings = PyDict_New();
-    psyco_encodings_fill(psycoEncodings);
+    if (!(psycoEncodings = PyDict_New())) { goto exit; }
+    if (0 != psyco_encodings_fill(psycoEncodings)) { goto exit; }
     psyco_null = Bytes_FromString("NULL");
-    psyco_DescriptionType = psyco_make_description_type();
+    if (!(psyco_DescriptionType = psyco_make_description_type())) { goto exit; }
 
     /* set some module's parameters */
     PyModule_AddStringConstant(module, "__version__", PSYCOPG_VERSION);
@@ -941,11 +999,11 @@ INIT_MODULE(_psycopg)(void)
     }
 #endif
     /* initialize default set of typecasters */
-    typecast_init(dict);
+    if (0 != typecast_init(dict)) { goto exit; }
 
     /* initialize microprotocols layer */
     microprotocols_init(dict);
-    psyco_adapters_init(dict);
+    if (0 != psyco_adapters_init(dict)) { goto exit; }
 
     /* create a standard set of exceptions and add them to the module's dict */
     if (0 != psyco_errors_init()) { goto exit; }
diff --git a/psycopg/typecast.c b/psycopg/typecast.c
index 8ede351c..8504631b 100644
--- a/psycopg/typecast.c
+++ b/psycopg/typecast.c
@@ -250,34 +250,28 @@ PyObject *psyco_default_binary_cast;
 
 /* typecast_init - initialize the dictionary and create default types */
 
-int
+RAISES_NEG int
 typecast_init(PyObject *dict)
 {
     int i;
+    int rv = -1;
+    typecastObject *t = NULL;
 
     /* create type dictionary and put it in module namespace */
-    psyco_types = PyDict_New();
-    psyco_binary_types = PyDict_New();
-
-    if (!psyco_types || !psyco_binary_types) {
-        Py_XDECREF(psyco_types);
-        Py_XDECREF(psyco_binary_types);
-        return -1;
-    }
-
+    if (!(psyco_types = PyDict_New())) { goto exit; }
     PyDict_SetItemString(dict, "string_types", psyco_types);
+
+    if (!(psyco_binary_types = PyDict_New())) { goto exit; }
     PyDict_SetItemString(dict, "binary_types", psyco_binary_types);
 
     /* insert the cast types into the 'types' dictionary and register them in
        the module dictionary */
     for (i = 0; typecast_builtins[i].name != NULL; i++) {
-        typecastObject *t;
-
         Dprintf("typecast_init: initializing %s", typecast_builtins[i].name);
 
         t = (typecastObject *)typecast_from_c(&(typecast_builtins[i]), dict);
-        if (t == NULL) return -1;
-        if (typecast_add((PyObject *)t, NULL, 0) != 0) return -1;
+        if (t == NULL) { goto exit; }
+        if (typecast_add((PyObject *)t, NULL, 0) < 0) { goto exit; }
 
         PyDict_SetItem(dict, t->name, (PyObject *)t);
 
@@ -285,6 +279,8 @@ typecast_init(PyObject *dict)
         if (typecast_builtins[i].values == typecast_BINARY_types) {
             psyco_default_binary_cast = (PyObject *)t;
         }
+        Py_DECREF((PyObject *)t);
+        t = NULL;
     }
 
     /* create and save a default cast object (but does not register it) */
@@ -294,29 +290,35 @@ typecast_init(PyObject *dict)
 #ifdef HAVE_MXDATETIME
     if (0 == psyco_typecast_mxdatetime_init()) {
         for (i = 0; typecast_mxdatetime[i].name != NULL; i++) {
-            typecastObject *t;
             Dprintf("typecast_init: initializing %s", typecast_mxdatetime[i].name);
             t = (typecastObject *)typecast_from_c(&(typecast_mxdatetime[i]), dict);
-            if (t == NULL) return -1;
+            if (t == NULL) { goto exit; }
             PyDict_SetItem(dict, t->name, (PyObject *)t);
+            Py_DECREF((PyObject *)t);
+            t = NULL;
         }
     }
 #endif
 
-    if (psyco_typecast_datetime_init()) { return -1; }
+    if (0 > psyco_typecast_datetime_init()) { goto exit; }
     for (i = 0; typecast_pydatetime[i].name != NULL; i++) {
-        typecastObject *t;
         Dprintf("typecast_init: initializing %s", typecast_pydatetime[i].name);
         t = (typecastObject *)typecast_from_c(&(typecast_pydatetime[i]), dict);
-        if (t == NULL) return -1;
+        if (t == NULL) { goto exit; }
         PyDict_SetItem(dict, t->name, (PyObject *)t);
+        Py_DECREF((PyObject *)t);
+        t = NULL;
     }
 
-    return 0;
+    rv = 0;
+
+exit:
+    Py_XDECREF((PyObject *)t);
+    return rv;
 }
 
 /* typecast_add - add a type object to the dictionary */
-int
+RAISES_NEG int
 typecast_add(PyObject *obj, PyObject *dict, int binary)
 {
     PyObject *val;
@@ -466,7 +468,7 @@ typecast_repr(PyObject *self)
 static PyObject *
 typecast_call(PyObject *obj, PyObject *args, PyObject *kwargs)
 {
-    char *string;
+    const char *string;
     Py_ssize_t length;
     PyObject *cursor;
 
diff --git a/psycopg/typecast.h b/psycopg/typecast.h
index 20def306..04976f31 100644
--- a/psycopg/typecast.h
+++ b/psycopg/typecast.h
@@ -71,8 +71,8 @@ extern HIDDEN PyObject *psyco_default_binary_cast;
 /** exported functions **/
 
 /* used by module.c to init the type system and register types */
-HIDDEN int typecast_init(PyObject *dict);
-HIDDEN int typecast_add(PyObject *obj, PyObject *dict, int binary);
+RAISES_NEG HIDDEN int typecast_init(PyObject *dict);
+RAISES_NEG HIDDEN int typecast_add(PyObject *obj, PyObject *dict, int binary);
 
 /* the C callable typecastObject creator function */
 HIDDEN PyObject *typecast_from_c(typecastObject_initlist *type, PyObject *d);
diff --git a/psycopg/typecast_array.c b/psycopg/typecast_array.c
index 75b84b50..b5f1062c 100644
--- a/psycopg/typecast_array.c
+++ b/psycopg/typecast_array.c
@@ -166,7 +166,7 @@ typecast_array_tokenize(const char *str, Py_ssize_t strlength,
     return res;
 }
 
-static int
+RAISES_NEG static int
 typecast_array_scan(const char *str, Py_ssize_t strlength,
                     PyObject *curs, PyObject *base, PyObject *array)
 {
@@ -199,7 +199,7 @@ typecast_array_scan(const char *str, Py_ssize_t strlength,
 
             /* before anything else we free the memory */
             if (state == ASCAN_QUOTED) PyMem_Free(token);
-            if (obj == NULL) return 0;
+            if (obj == NULL) return -1;
 
             PyList_Append(array, obj);
             Py_DECREF(obj);
@@ -207,25 +207,25 @@ typecast_array_scan(const char *str, Py_ssize_t strlength,
 
         else if (state == ASCAN_BEGIN) {
             PyObject *sub = PyList_New(0);
-            if (sub == NULL) return 0;
+            if (sub == NULL) return -1;
 
             PyList_Append(array, sub);
             Py_DECREF(sub);
 
             if (stack_index == MAX_DIMENSIONS)
-                return 0;
+                return -1;
 
             stack[stack_index++] = array;
             array = sub;
         }
 
         else if (state == ASCAN_ERROR) {
-            return 0;
+            return -1;
         }
 
         else if (state == ASCAN_END) {
             if (--stack_index < 0)
-                return 0;
+                return -1;
             array = stack[stack_index];
         }
 
@@ -233,7 +233,7 @@ typecast_array_scan(const char *str, Py_ssize_t strlength,
             break;
     }
 
-    return 1;
+    return 0;
 }
 
 
@@ -260,12 +260,11 @@ typecast_GENERIC_ARRAY_cast(const char *str, Py_ssize_t len, PyObject *curs)
     Dprintf("typecast_GENERIC_ARRAY_cast: str = '%s',"
             " len = " FORMAT_CODE_PY_SSIZE_T, str, len);
 
-    obj = PyList_New(0);
+    if (!(obj = PyList_New(0))) { return NULL; }
 
     /* scan the array skipping the first level of {} */
-    if (typecast_array_scan(&str[1], len-2, curs, base, obj) == 0) {
-        Py_DECREF(obj);
-        obj = NULL;
+    if (typecast_array_scan(&str[1], len-2, curs, base, obj) < 0) {
+        Py_CLEAR(obj);
     }
 
     return obj;
diff --git a/psycopg/typecast_basic.c b/psycopg/typecast_basic.c
index 20c7b81f..5e2a93ea 100644
--- a/psycopg/typecast_basic.c
+++ b/psycopg/typecast_basic.c
@@ -65,7 +65,7 @@ typecast_FLOAT_cast(const char *s, Py_ssize_t len, PyObject *curs)
     PyObject *str = NULL, *flo = NULL;
 
     if (s == NULL) {Py_INCREF(Py_None); return Py_None;}
-    str = Text_FromUTF8AndSize(s, len);
+    if (!(str = Text_FromUTF8AndSize(s, len))) { return NULL; }
 #if PY_MAJOR_VERSION < 3
     flo = PyFloat_FromString(str, NULL);
 #else
diff --git a/psycopg/typecast_datetime.c b/psycopg/typecast_datetime.c
index 29149c05..18e9d0d8 100644
--- a/psycopg/typecast_datetime.c
+++ b/psycopg/typecast_datetime.c
@@ -26,7 +26,7 @@
 #include <math.h>
 #include "datetime.h"
 
-static int
+RAISES_NEG static int
 psyco_typecast_datetime_init(void)
 {
     Dprintf("psyco_typecast_datetime_init: datetime init");
@@ -239,7 +239,7 @@ typecast_PYINTERVAL_cast(const char *str, Py_ssize_t len, PyObject *curs)
 
         case '0': case '1': case '2': case '3': case '4':
         case '5': case '6': case '7': case '8': case '9':
-            v = v*10 + (double)*str - (double)'0';
+            v = v * 10.0 + (double)(*str - '0');
             if (part == 6){
                 denominator *= 10;
             }
diff --git a/psycopg/typecast_mxdatetime.c b/psycopg/typecast_mxdatetime.c
index e61224df..bf69af5a 100644
--- a/psycopg/typecast_mxdatetime.c
+++ b/psycopg/typecast_mxdatetime.c
@@ -142,7 +142,7 @@ typecast_MXINTERVAL_cast(const char *str, Py_ssize_t len, PyObject *curs)
 
         case '0': case '1': case '2': case '3': case '4':
         case '5': case '6': case '7': case '8': case '9':
-            v = v*10 + (double)*str - (double)'0';
+            v = v * 10.0 + (double)(*str - '0');
             Dprintf("typecast_MXINTERVAL_cast: v = %f", v);
             if (part == 6){
                 denominator *= 10;
diff --git a/psycopg/utils.c b/psycopg/utils.c
index 2e81c113..57586c57 100644
--- a/psycopg/utils.c
+++ b/psycopg/utils.c
@@ -113,20 +113,19 @@ psycopg_escape_identifier_easy(const char *from, Py_ssize_t len)
  * Allocate a new buffer on the Python heap containing the new string.
  * 'len' is optional: if 0 the length is calculated.
  *
- * Return NULL and set an exception in case of error.
+ * Store the return in 'to' and return 0 in case of success, else return -1
+ * and raise an exception.
  */
-char *
-psycopg_strdup(const char *from, Py_ssize_t len)
+RAISES_NEG int
+psycopg_strdup(char **to, const char *from, Py_ssize_t len)
 {
-    char *rv;
-
     if (!len) { len = strlen(from); }
-    if (!(rv = PyMem_Malloc(len + 1))) {
+    if (!(*to = PyMem_Malloc(len + 1))) {
         PyErr_NoMemory();
-        return NULL;
+        return -1;
     }
-    strcpy(rv, from);
-    return rv;
+    strcpy(*to, from);
+    return 0;
 }
 
 /* Ensure a Python object is a bytes string.
@@ -139,7 +138,7 @@ psycopg_strdup(const char *from, Py_ssize_t len)
  *
  * It is safe to call the function on NULL.
  */
-PyObject *
+STEALS(1) PyObject *
 psycopg_ensure_bytes(PyObject *obj)
 {
     PyObject *rv = NULL;
@@ -169,7 +168,7 @@ psycopg_ensure_bytes(PyObject *obj)
  * The function is ref neutral: steals a ref from obj and adds one to the
  * return value.  It is safe to call it on NULL.
  */
-PyObject *
+STEALS(1) PyObject *
 psycopg_ensure_text(PyObject *obj)
 {
 #if PY_MAJOR_VERSION < 3
diff --git a/psycopg/xid_type.c b/psycopg/xid_type.c
index 4de46b44..b28543ca 100644
--- a/psycopg/xid_type.c
+++ b/psycopg/xid_type.c
@@ -78,7 +78,9 @@ static PyMemberDef xid_members[] = {
 static PyObject *
 xid_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
 {
-    XidObject *self = (XidObject *)type->tp_alloc(type, 0);
+    XidObject *self;
+
+    if (!(self = (XidObject *)type->tp_alloc(type, 0))) { return NULL; }
 
     Py_INCREF(Py_None);
     self->format_id = Py_None;
@@ -486,7 +488,7 @@ exit:
  *
  * Return a borrowed reference. */
 
-static PyObject *
+BORROWED static PyObject *
 _xid_get_parse_regex(void) {
     static PyObject *rv;