fix(generator): handle ptrdiff_t type correctly in C type mapping

Adds special case handling for ptrdiff_t in getCType function to preserve its
type name rather than converting it to a Go equivalent.

This fixes type mismatch errors on macOS where ptrdiff_t is a distinct type
from int64_t despite having the same size.

Author: flexiondotorg

functions.gen.go

@@ -14172,7 +14172,7 @@ func AVImageCopyPlane(dst unsafe.Pointer, dstLinesize int, src unsafe.Pointer, s
         size (i.e. 64) to get improved performance.
 */
 func AVImageCopyPlaneUcFrom(dst unsafe.Pointer, dstLinesize int64, src unsafe.Pointer, srcLinesize int64, bytewidth int64, height int) {
-	C.av_image_copy_plane_uc_from((*C.uint8_t)(dst), C.int64_t(dstLinesize), (*C.uint8_t)(src), C.int64_t(srcLinesize), C.int64_t(bytewidth), C.int(height))
+	C.av_image_copy_plane_uc_from((*C.uint8_t)(dst), C.ptrdiff_t(dstLinesize), (*C.uint8_t)(src), C.ptrdiff_t(srcLinesize), C.ptrdiff_t(bytewidth), C.int(height))
 }
 
 // --- Function av_image_copy ---

internal/generator/generator.go

@@ -87,6 +87,13 @@ func getCType(typeName string, goType string) string {
 		return "char"
 	}
 
+	// Special case: ptrdiff_t and size_t must be preserved
+	// On macOS, ptrdiff_t is a distinct type from int64_t even though they're the same size
+	// Using C.int64_t instead of C.ptrdiff_t causes type mismatch errors
+	if typeName == "ptrdiff_t" {
+		return "ptrdiff_t"
+	}
+
 	// Map Go types to their correct C types
 	// Returns the type name to use after "C." in generated code
 	switch goType {