diff --git a/sha1_file.c b/sha1_file.c
index 88035a0..0cfea9e 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -2280,7 +2280,8 @@
 static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
 			      void *buf, unsigned long len, time_t mtime)
 {
-	int fd, size, ret;
+	int fd, ret;
+	size_t size;
 	unsigned char *compressed;
 	z_stream stream;
 	char *filename;