diff --git a/src/common/util.h b/src/common/util.h
index 8b2762fb..2c9f790c 100644
--- a/src/common/util.h
+++ b/src/common/util.h
@@ -80,5 +80,5 @@ char *encode_sasl_pass_blowfish (char *user, char *pass, char *data);
 char *encode_sasl_pass_aes (char *user, char *pass, char *data);
 char *challengeauth_response (char *username, char *password, char *challenge);
 size_t strftime_validated (char *dest, size_t destsize, const char *format, const struct tm *time);
-size_t strftime_utf8 (char *dest, size_t destsize, const char *format, time_t time);
+gsize strftime_utf8 (char *dest, gsize destsize, const char *format, time_t time);
 #endif