diff --git a/src/proto/filepath.pro b/src/proto/filepath.pro
index 2979b73..260f407 100644
--- a/src/proto/filepath.pro
+++ b/src/proto/filepath.pro
@@ -55,7 +55,7 @@
 int expand_wildcards_eval(char_u **pat, int *num_file, char_u ***file, int flags);
 int expand_wildcards(int num_pat, char_u **pat, int *num_files, char_u ***files, int flags);
 int match_suffix(char_u *fname);
-int unix_expandpath(garray_T *gap, char_u *path, int wildoff, int flags, int didstar);
+int unix_expandpath(garray_T *gap, char_u *path, size_t wildoff, int flags, int didstar);
 int gen_expand_wildcards(int num_pat, char_u **pat, int *num_file, char_u ***file, int flags);
 void addfile(garray_T *gap, char_u *f, int flags);
 void FreeWild(int count, char_u **files);