diff --git a/search.c b/search.c
index c3d5393869a5527c4cdf3464f9971f0a9d39c2fc..7afab58df0c7a52572ab53fed0b5401725f7c676 100644
--- a/search.c
+++ b/search.c
@@ -339,7 +339,7 @@ int replace_regexp(char *string, int create_flag)
 }
 #endif
 
-char *replace_line()
+char *replace_line(void)
 {
     char *copy, *tmp;
     int new_line_size;