Add %V format specifier (returns feh PID) - patch by 0ion9, closse #109

man/feh.pre

@@ -873,6 +873,10 @@ Image width
 .Nm
 version
 .
+.It %V
+.
+Process ID
+.
 .It %z
 .
 current image zoom

src/slideshow.c

@@ -508,6 +508,10 @@ char *feh_printf(char *str, feh_file * file, winwidget winwid)
 			case 'v':
 				strcat(ret, VERSION);
 				break;
+			case 'V':
+				snprintf(buf, sizeof(buf), "%d", getpid());
+				strcat(ret, buf);
+				break;
 			case 'w':
 				if (file && (file->info || !feh_file_info_load(file, NULL))) {
 					snprintf(buf, sizeof(buf), "%d", file->info->width);