Show usage and exit non-zero for unsupported option in mm2gv

Towards https://gitlab.com/graphviz/graphviz/-/issues/1843.

diff --git a/cmd/tools/mm2gv.c b/cmd/tools/mm2gv.c
index 9ce50baff2f02869f7863c801f594a6cdcad9d70..0bf67c189b26f12b37999546e0b417e049c06981 100644 (file)
--- a/cmd/tools/mm2gv.c
+++ b/cmd/tools/mm2gv.c
@@ -423,10 +423,12 @@ static void init(int argc, char **argv, parms_t * p)
        case '?':
            if (optopt == '?')
                usage(0);
-           else
+           else {
                fprintf(stderr,
-                       "%s: option -%c unrecognized - ignored\n", cmd,
+                       "%s: option -%c unrecognized\n", cmd,
                        optopt);
+               usage(1);
+           }
            break;
        }
     }