Fix gvedit -? to actually print usage instead of error

Fixes https://gitlab.com/graphviz/graphviz/-/issues/1813

diff --git a/cmd/gvedit/main.cpp b/cmd/gvedit/main.cpp
index bb4c2546b58d7e0cfac39066c5c648dd31f7772e..76a0ed6434020a19c34183c7d0116136443b4ee9 100644 (file)
--- a/cmd/gvedit/main.cpp
+++ b/cmd/gvedit/main.cpp
@@ -66,7 +66,7 @@ static char **parseArgs(int argc, char *argv[])
            Verbose = 1;
            break;
        case '?':
-           if (optopt == '?')
+           if (optopt == '\0')
                usage(0);
            else
                errout << cmd << " : option -" << ((char) optopt) <<