Breaking out the usage bit, other mindless crap.

digressions/getopt-example.c

@@ -4,17 +4,29 @@
 #include <unistd.h>
 #include <stdlib.h>
 #include <stdio.h>
+#include <libgen.h>
 
-int
-main(int argc, char *argv[])
-{
+
+void die_usage(char *prog, char *msg) {
+    fprintf(stderr, "Usage: %s [-t nsecs] [-n] name\n", prog);
+    if (msg != NULL) {
+        fprintf(stderr, "%s\n", msg);
+    }
+    exit(EXIT_FAILURE);
+}
+
+
+int main(int argc, char *argv[]) {
+    char *prog;
     int flags, opt;
     int nsecs, tfnd;
 
     nsecs = 0;
     tfnd = 0;
     flags = 0;
-    while ((opt = getopt(argc, argv, "nt:")) != -1) {
+    prog = basename(argv[0]);
+
+    while ((opt = getopt(argc, argv, "hnt:")) != -1) {
         switch (opt) {
         case 'n':
             flags = 1;
@@ -23,23 +35,20 @@ main(int argc, char *argv[])
             nsecs = atoi(optarg);
             tfnd = 1;
             break;
+        case 'h':
         default: /* '?' */
-            fprintf(stderr, "Usage: %s [-t nsecs] [-n] name\n",
-                    argv[0]);
-            exit(EXIT_FAILURE);
+            die_usage(prog, NULL);
         }
     }
 
     printf("flags=%d; tfnd=%d; optind=%d\n", flags, tfnd, optind);
 
     if (optind >= argc) {
-        fprintf(stderr, "Expected argument after options\n");
-        exit(EXIT_FAILURE);
+        die_usage(prog, "Expected argument after options");
     }
 
     printf("name argument = %s\n", argv[optind]);
-
-    /* Other code omitted */
+    printf("nsecs = %d\n", nsecs);
 
     exit(EXIT_SUCCESS);
 }