1 files changed, 1 insertions, 1 deletions
diff --git a/snac.c b/snac.c
index f461280..8afe1f8 100644
--- a/snac.c
+++ b/snac.c
@@ -93,7 +93,7 @@ int validate_uid(const char *uid)
         return 0;
 
     while (*uid) {
-        if (!(isalnum(*uid) || *uid == '_'))
+        if (!(isalnum((int)*uid) || *uid == '_'))
             return 0;
 
         uid++;