Can now choose the mixer device from the command line

src/main.c

@@ -26,7 +26,8 @@
 /* usage */
 static int _usage(void)
 {
-	fputs("Usage: " PACKAGE "\n", stderr);
+	fputs("Usage: " PACKAGE " [-d device]\n"
+"  -d	The mixer device to use\n", stderr);
 	return 1;
 }
 
@@ -35,18 +36,23 @@ static int _usage(void)
 int main(int argc, char * argv[])
 {
 	int o;
+	char const * device = NULL;
 	Mixer * mixer;
 
-	while((o = getopt(argc, argv, "")) != -1)
+	while((o = getopt(argc, argv, "d:")) != -1)
 		switch(o)
 		{
+			case 'd':
+				device = optarg;
+				break;
 			default:
 				return _usage();
 		}
 	if(optind != argc)
 		return _usage();
 	gtk_init(&argc, &argv);
-	mixer = mixer_new();
+	if((mixer = mixer_new(device)) == NULL)
+		return 2;
 	gtk_main();
 	mixer_delete(mixer);
 	return 0;

src/mixer.c

@@ -111,7 +111,7 @@ static GtkWidget * _new_set(Mixer * mixer, int dev, struct audio_mixer_set * s);
 static GtkWidget * _new_value(Mixer * mixer, int dev,
 		struct audio_mixer_value * v);
 
-Mixer * mixer_new(void)
+Mixer * mixer_new(char const * device)
 {
 	Mixer * mixer;
 	GtkAccelGroup * group;
@@ -127,7 +127,9 @@ Mixer * mixer_new(void)
 
 	if((mixer = malloc(sizeof(*mixer))) == NULL)
 		return NULL;
-	mixer->fd = open("/dev/mixer", O_RDWR);
+	if(device == NULL)
+		device = "/dev/mixer";
+	mixer->fd = open(device, O_RDWR);
 	mixer->window = NULL;
 	mixer->properties = NULL;
 	mixer->about = NULL;
@@ -135,6 +137,8 @@ Mixer * mixer_new(void)
 	mixer->mc_cnt = 0;
 	if(mixer->fd < 0)
 	{
+		fprintf(stderr, "%s: %s: %s\n", PACKAGE, device,
+				strerror(errno));
 		mixer_delete(mixer);
 		return NULL;
 	}

src/mixer.h

@@ -27,7 +27,7 @@ typedef struct _Mixer Mixer;
 
 
 /* functions */
-Mixer * mixer_new(void);
+Mixer * mixer_new(char const * device);
 void mixer_delete(Mixer * mixer);
 
 /* accessors */