diff --git a/ChangeLog b/ChangeLog
index 255181387..4665692a4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2015-09-26  Werner Lemberg  <wl@gnu.org>
+
+	[bzip2, gzip, lzw] Harmonize function signatures with prototype.
+
+	Suggested by Hin-Tak Leung.
+
+	* src/bzip2/ftbzip2.c (ft_bzip2_stream_io), src/gzip/ftgzip.c
+	(ft_gzip_stream_io), src/lzw/ftlzw.c (ft_lzw_stream_io): Do it.
+
 2015-09-26  Hin-Tak Leung  <htl10@users.sourceforge.net>
 
 	Add new FT_LOAD_COMPUTE_METRICS load flag.
diff --git a/src/bzip2/ftbzip2.c b/src/bzip2/ftbzip2.c
index 4dfc9c899..86f8be8b7 100644
--- a/src/bzip2/ftbzip2.c
+++ b/src/bzip2/ftbzip2.c
@@ -437,16 +437,16 @@
   }
 
 
-  static FT_ULong
-  ft_bzip2_stream_io( FT_Stream  stream,
-                      FT_ULong   pos,
-                      FT_Byte*   buffer,
-                      FT_ULong   count )
+  static unsigned long
+  ft_bzip2_stream_io( FT_Stream       stream,
+                      unsigned long   offset,
+                      unsigned char*  buffer,
+                      unsigned long   count )
   {
     FT_BZip2File  zip = (FT_BZip2File)stream->descriptor.pointer;
 
 
-    return ft_bzip2_file_io( zip, pos, buffer, count );
+    return ft_bzip2_file_io( zip, offset, buffer, count );
   }
 
 
diff --git a/src/gzip/ftgzip.c b/src/gzip/ftgzip.c
index be9c122a2..452768b64 100644
--- a/src/gzip/ftgzip.c
+++ b/src/gzip/ftgzip.c
@@ -563,16 +563,16 @@
   }
 
 
-  static FT_ULong
-  ft_gzip_stream_io( FT_Stream  stream,
-                     FT_ULong   pos,
-                     FT_Byte*   buffer,
-                     FT_ULong   count )
+  static unsigned long
+  ft_gzip_stream_io( FT_Stream       stream,
+                     unsigned long   offset,
+                     unsigned char*  buffer,
+                     unsigned long   count )
   {
     FT_GZipFile  zip = (FT_GZipFile)stream->descriptor.pointer;
 
 
-    return ft_gzip_file_io( zip, pos, buffer, count );
+    return ft_gzip_file_io( zip, offset, buffer, count );
   }
 
 
diff --git a/src/lzw/ftlzw.c b/src/lzw/ftlzw.c
index 5664ff9cf..2f4e3b0f1 100644
--- a/src/lzw/ftlzw.c
+++ b/src/lzw/ftlzw.c
@@ -330,16 +330,16 @@
   }
 
 
-  static FT_ULong
-  ft_lzw_stream_io( FT_Stream  stream,
-                    FT_ULong   pos,
-                    FT_Byte*   buffer,
-                    FT_ULong   count )
+  static unsigned long
+  ft_lzw_stream_io( FT_Stream       stream,
+                    unsigned long   offset,
+                    unsigned char*  buffer,
+                    unsigned long   count )
   {
     FT_LZWFile  zip = (FT_LZWFile)stream->descriptor.pointer;
 
 
-    return ft_lzw_file_io( zip, pos, buffer, count );
+    return ft_lzw_file_io( zip, offset, buffer, count );
   }