diff --git a/lib/libsys/optset.c b/lib/libsys/optset.c
index fe9bedaea..f3ef2a006 100644
--- a/lib/libsys/optset.c
+++ b/lib/libsys/optset.c
@@ -55,7 +55,7 @@ int len;
 
   case OPT_INT:
 	if (len > 0)
-		val = strtol(ptr, NULL, entry->os_val);
+		val = (int) strtoul(ptr, NULL, entry->os_val);
 	else
 		val = 0;