* Calls the specified function for each ref file until it returns nonzero,
* and returns the value
*/
-extern int for_each_ref(int (*fn)(const char *path, unsigned char *sha1));
+extern int head_ref(int (*fn)(const char *path, const unsigned char *sha1));
+extern int for_each_ref(int (*fn)(const char *path, const unsigned char *sha1));
/** Reads the refs file specified into sha1 **/
extern int get_ref_sha1(const char *ref, unsigned char *sha1);