diff --git a/fortune-mod/fortune/fortune.c b/fortune-mod/fortune/fortune.c
index 49cedb4..dc11d7d 100644
--- a/fortune-mod/fortune/fortune.c
+++ b/fortune-mod/fortune/fortune.c
@@ -290,7 +290,7 @@ void usage(void)
  *      Translate text from UTF-8 to current CODESET (LC_CTYPE).
  * Thanx to Alexander Bokovoy for this code.
  */
-int fortune_iconv(iconv_t _cd, char *inbuf, int inlen, char *outbuf, int outlen)
+int fortune_iconv(iconv_t _cd, char *inbuf, size_t inlen, char *outbuf, size_t outlen)
 {
     char *outptr;
     size_t n;