added daemonization, output possibility to console (for other programs) and moved the code to set WM_NAME to its own function as it is needed two times

arg.h

@@ -0,0 +1,55 @@
+/*
+ * Copy me if you can.
+ * by 20h
+ */
+
+#ifndef __ARG_H__
+#define __ARG_H__
+
+extern char *argv0;
+
+#define USED(x)		((void)(x))
+
+/* use main(int argc, char *argv[]) */
+#define ARGBEGIN	for (argv0 = *argv, argv++, argc--;\
+					argv[0] && argv[0][1]\
+					&& argv[0][0] == '-';\
+					argc--, argv++) {\
+				char _argc;\
+				char **_argv;\
+				int brk;\
+				if (argv[0][1] == '-' && argv[0][2] == '\0') {\
+					argv++;\
+					argc--;\
+					break;\
+				}\
+				for (brk = 0, argv[0]++, _argv = argv;\
+						argv[0][0] && !brk;\
+						argv[0]++) {\
+					if (_argv != argv)\
+						break;\
+					_argc = argv[0][0];\
+					switch (_argc)
+
+#define ARGEND			}\
+				USED(_argc);\
+			}\
+			USED(argv);\
+			USED(argc);
+
+#define ARGC()		_argc
+
+#define EARGF(x)	((argv[0][1] == '\0' && argv[1] == NULL)?\
+				((x), abort(), (char *)0) :\
+				(brk = 1, (argv[0][1] != '\0')?\
+					(&argv[0][1]) :\
+					(argc--, argv++, argv[0])))
+
+#define ARGF()		((argv[0][1] == '\0' && argv[1] == NULL)?\
+				(char *)0 :\
+				(brk = 1, (argv[0][1] != '\0')?\
+					(&argv[0][1]) :\
+					(argc--, argv++, argv[0])))
+
+#endif
+

slstatus.c

@@ -26,6 +26,7 @@
 #undef strlcat
 #undef strlcpy
 
+#include "arg.h"
 #include "strlcat.h"
 #include "strlcpy.h"
 #include "concat.h"
@@ -64,9 +65,12 @@ static char *username(void);
 static char *vol_perc(const char *);
 static char *wifi_perc(const char *);
 static char *wifi_essid(const char *);
+static void set_status(const char *);
 static void sighandler(const int);
+static void usage(void);
 
-static unsigned short int delay, done;
+char *argv0;
+static unsigned short int delay, done, dflag, oflag;
 static Display *dpy;
 
 #include "config.h"
@@ -579,6 +583,13 @@ wifi_essid(const char *wificard)
 		return smprintf("%s", (char *)wreq.u.essid.pointer);
 }
 
+static void
+set_status(const char *str)
+{
+	XStoreName(dpy, DefaultRootWindow(dpy), str);
+	XSync(dpy, False);
+}
+
 static void
 sighandler(const int signo)
 {
@@ -586,8 +597,20 @@ sighandler(const int signo)
 		done = 1;
 }
 
+static void
+usage(void)
+{
+	fprintf(stderr,
+		"slstatus (c) 2016, drkhsh\n"
+		"usage: %s [-dho]\n",
+		argv0);
+	exit(1);
+}
+
+
+
 int
-main(void)
+main(int argc, char *argv[])
 {
 	unsigned short int i;
 	char status_string[4096];
@@ -595,6 +618,22 @@ main(void)
 	struct arg argument;
 	struct sigaction act;
 
+	ARGBEGIN {
+		case 'd':
+			dflag = 1;
+			break;
+		case 'o':
+			oflag = 1;
+			break;
+		default:
+			usage();
+	} ARGEND
+
+	if (dflag && oflag)
+		usage();
+	if (dflag)
+		(void)daemon(1, 1);
+
 	memset(&act, 0, sizeof(act));
 	act.sa_handler = sighandler;
 	sigaction(SIGINT,  &act, 0);
@@ -604,6 +643,7 @@ main(void)
 
 	while (!done) {
 		status_string[0] = '\0';
+
 		for (i = 0; i < sizeof(args) / sizeof(args[0]); ++i) {
 			argument = args[i];
 			if (argument.args == NULL)
@@ -619,8 +659,12 @@ main(void)
 			free(res);
 			free(element);
 		}
-		XStoreName(dpy, DefaultRootWindow(dpy), status_string);
-		XSync(dpy, False);
+
+		if (!oflag)
+			set_status(status_string);
+		else
+			printf("%s\n", status_string);
+
 		/*
 		 * subtract delay time spend in function
 		 * calls from the actual global delay time
@@ -629,8 +673,8 @@ main(void)
 		delay = 0;
 	}
 
-	XStoreName(dpy, DefaultRootWindow(dpy), NULL);
-	XSync(dpy, False);
+	if (!oflag)
+		set_status(NULL);
 
 	XCloseDisplay(dpy);