diff --git a/src/libImaging/TiffDecode.h b/src/libImaging/TiffDecode.h
index e29a6c88f..1c1337715 100644
--- a/src/libImaging/TiffDecode.h
+++ b/src/libImaging/TiffDecode.h
@@ -43,7 +43,7 @@ typedef struct {
 
 
 
-extern int ImagingLibTiffInit(ImagingCodecState state, int fp, int offset);
+extern int ImagingLibTiffInit(ImagingCodecState state, int fp, uint32 offset);
 extern int ImagingLibTiffEncodeInit(ImagingCodecState state, char *filename, int fp);
 extern int ImagingLibTiffMergeFieldInfo(ImagingCodecState state, TIFFDataType field_type, int key);
 extern int ImagingLibTiffSetField(ImagingCodecState state, ttag_t tag, ...);