diff --git a/ares/ares_getopt.c b/ares/ares_getopt.c
index 3b565a49a1a6e1b8a045a3b0435e262fc0d3ac9f..177b26feaeed389e115b36f4380e12fee48f2451 100644
--- a/ares/ares_getopt.c
+++ b/ares/ares_getopt.c
@@ -82,7 +82,7 @@ ares_getopt(int nargc, char * const nargv[], const char *ostr)
         }
     }                                         /* option letter okay? */
     if ((optopt = (int)*place++) == (int)':' ||
-        !(oli = strchr(ostr, optopt))) {
+        (oli = strchr(ostr, optopt)) == NULL) {
         /*
          * if the user didn't specify '-' as an option,
          * assume it means EOF.