Wavefile playback

* Corrected fault when trying to playback a stereo wavefile
  * Leonardo is not yet a ham, but credits his interest to
    his grandfather, I5LAP

src/dialogs/fl_digi.cxx

@@ -1608,7 +1608,23 @@ void cb_mnuPlayback(Fl_Widget *w, void *d)
 		return;
 	}
 	playval = m->value();
-	if(!scard->Playback(playval)) {
+
+	int err = scard->Playback(playval);
+
+	if(err < 0) {
+		switch (err) {
+			case -1:
+				fl_alert2(_("No file name given"));
+				break;
+			case -2:
+				fl_alert2(_("Unsupported format"));
+				break;
+			case -3:
+				fl_alert2(_("channels != 1"));
+				break;
+			default:
+				fl_alert2(_("unknown wave file error"));
+		}
 		m->clear();
 		playval = false;
 	}
@@ -4442,7 +4458,7 @@ void create_fl_digi_main_primary() {
 			const char *label6a = _("# R");
 			const char *label7a = _("Ex");
 			const char *xData = "00000";
-			const char *xCall = "WW8WWW/WWWW";
+			const char *xCall = "WW8WWW";//"WW8WWW/WWWW";
 			int   wData = static_cast<int>(fl_width(xData));
 			int   wCall = static_cast<int>(fl_width(xCall));
 

src/soundcard/sound.cxx

@@ -186,16 +186,21 @@ int SoundBase::Playback(bool val)
 	int format;
 	get_file_params("playback.wav", &fname, &format);
 	if (!fname)
-		return 0;
+		return -1;
 
 	SF_INFO info = { 0, 0, 0, 0, 0, 0 };
 	if ((ifPlayback = sf_open(fname, SFM_READ, &info)) == NULL) {
 		LOG_ERROR("Could not read %s:%s", fname, sf_strerror(NULL) );
-		return 0;
+		return -2;
 	}
 
+ 	if (info.channels != 1) {
+ 		sf_close(ifPlayback);
+ 		return -3;
+ 	}
+
 	playback = true;
-	return 1;
+	return 0;
 }
 
 int SoundBase::Generate(bool val)