Print which option was in error along with usage message

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>

1 files changed, 13 insertions, 6 deletions

diff --git a/xkill.c b/xkill.c
index 2270dcd..32cb0cc 100644
--- a/xkill.c
+++ b/xkill.c
@@ -73,7 +73,7 @@ Exit(int code, Display *dpy)
 }
 
 static void _X_NORETURN
-usage(void)
+usage(const char *errmsg)
 {
     const char *options =
 "where options include:\n"
@@ -85,6 +85,9 @@ usage(void)
 "    -version                print version and exit\n"
 "\n";
 
+    if (errmsg != NULL)
+        fprintf (stderr, "%s: %s\n\n", ProgramName, errmsg);
+
     fprintf (stderr, "usage:  %s [-option ...]\n%s",
 	     ProgramName, options);
     Exit (1, NULL);
@@ -112,11 +115,11 @@ main(int argc, char *argv[])
 	if (arg[0] == '-') {
 	    switch (arg[1]) {
 	      case 'd':			/* -display displayname */
-		if (++i >= argc) usage ();
+		if (++i >= argc) usage ("-display requires an argument");
 		displayname = argv[i];
 		continue;
 	      case 'i':			/* -id resourceid */
-		if (++i >= argc) usage ();
+		if (++i >= argc) usage ("-id requires an argument");
 		id = strtoul (argv[i], NULL, 0);
 		if (id == 0 || id >= 0xFFFFFFFFU) {
 		    fprintf (stderr, "%s:  invalid id \"%s\"\n",
@@ -125,7 +128,7 @@ main(int argc, char *argv[])
 		}
 		continue;
 	      case 'b':			/* -button number */
-		if (++i >= argc) usage ();
+		if (++i >= argc) usage ("-button requires an argument");
 		button_name = argv[i];
 		continue;
 	      case 'f':			/* -frame */
@@ -138,10 +141,14 @@ main(int argc, char *argv[])
                 puts(PACKAGE_STRING);
                 exit(0);
 	      default:
-		usage ();
+                fprintf(stderr, "%s: unrecognized argument %s\n\n",
+                        ProgramName, arg);
+		usage (NULL);
 	    }
 	} else {
-	    usage ();
+            fprintf(stderr, "%s: unrecognized argument %s\n\n",
+                    ProgramName, arg);
+            usage (NULL);
 	}
     }					/* end for */