Explicitly specify -? as an option in cluster

diff --git a/cmd/gvmap/cluster.c b/cmd/gvmap/cluster.c
index bf97ace4bf65a5af4ef98757b40c4e03e8d92f3d..e5232bac96a042ac4ea2a4f56ab7889231cf4b87 100644 (file)
--- a/cmd/gvmap/cluster.c
+++ b/cmd/gvmap/cluster.c
@@ -99,7 +99,7 @@ static void init(int argc, char *argv[], opts_t* opts) {
   Verbose = 0;
 
   opts->clustering_method =  CLUSTERING_MODULARITY;
-  while ((c = getopt(argc, argv, ":vC:c:o:")) != -1) {
+  while ((c = getopt(argc, argv, ":vC:c:o:?")) != -1) {
     switch (c) {
     case 'c':
       if ((sscanf(optarg,"%d", &v) == 0) || (v < 0)) {
@@ -120,7 +120,7 @@ static void init(int argc, char *argv[], opts_t* opts) {
       Verbose = 1;
       break;
     case '?':
-      if (optopt == '?')
+      if (optopt == '\0')
        usage(cmd, 0);
       else {
        fprintf(stderr, " option -%c unrecognized\n",