diff --git a/src/proto/misc2.pro b/src/proto/misc2.pro
index 5f7d709..5ecd595 100644
--- a/src/proto/misc2.pro
+++ b/src/proto/misc2.pro
@@ -43,7 +43,7 @@
 int ga_grow(garray_T *gap, int n);
 int ga_grow_inner(garray_T *gap, int n);
 char_u *ga_concat_strings(garray_T *gap, char *sep);
-void ga_add_string(garray_T *gap, char_u *p);
+int ga_add_string(garray_T *gap, char_u *p);
 void ga_concat(garray_T *gap, char_u *s);
 void ga_append(garray_T *gap, int c);
 void append_ga_line(garray_T *gap);