make use of EXIT_ macros

commands.c

@@ -48,7 +48,7 @@ extern int filecnt, fileidx;
 
 bool it_quit(arg_t a) {
 	cleanup();
-	exit(0);
+	exit(EXIT_SUCCESS);
 }
 
 bool it_switch_mode(arg_t a) {
@@ -388,7 +388,7 @@ bool it_open_with(arg_t a) {
 		execlp(prog, prog,
 		       files[mode == MODE_IMAGE ? fileidx : tns.sel].path, NULL);
 		warn("could not exec: %s", prog);
-		exit(1);
+		exit(EXIT_FAILURE);
 	} else if (pid < 0) {
 		warn("could not fork. program was: %s", prog);
 	}
@@ -415,7 +415,7 @@ bool it_shell_cmd(arg_t a) {
 	if ((pid = fork()) == 0) {
 		execl("/bin/sh", "/bin/sh", "-c", cmdline, NULL);
 		warn("could not exec: /bin/sh. command line was: %s", cmdline);
-		exit(1);
+		exit(EXIT_FAILURE);
 	} else if (pid < 0) {
 		warn("could not fork. command line was: %s", cmdline);
 		return false;

main.c

@@ -471,12 +471,12 @@ int main(int argc, char **argv) {
 	if (options->clean_cache) {
 		tns_init(&tns, 0, NULL);
 		tns_clean_cache(&tns);
-		exit(0);
+		exit(EXIT_SUCCESS);
 	}
 
 	if (!options->filecnt) {
 		print_usage();
-		exit(1);
+		exit(EXIT_FAILURE);
 	}
 
 	if (options->recursive || options->from_stdin)
@@ -526,7 +526,7 @@ int main(int argc, char **argv) {
 
 	if (!fileidx) {
 		fprintf(stderr, "sxiv: no valid image file given, aborting\n");
-		exit(1);
+		exit(EXIT_FAILURE);
 	}
 
 	filecnt = fileidx;

options.c

@@ -75,7 +75,7 @@ void parse_options(int argc, char **argv) {
 		switch (opt) {
 			case '?':
 				print_usage();
-				exit(1);
+				exit(EXIT_FAILURE);
 			case 'c':
 				_options.clean_cache = true;
 				break;
@@ -93,12 +93,12 @@ void parse_options(int argc, char **argv) {
 				break;
 			case 'h':
 				print_usage();
-				exit(0);
+				exit(EXIT_SUCCESS);
 			case 'n':
 				if (!sscanf(optarg, "%d", &t) || t < 1) {
 					fprintf(stderr, "sxiv: invalid argument for option -n: %s\n",
 					        optarg);
-					exit(1);
+					exit(EXIT_FAILURE);
 				} else {
 					_options.startnum = t - 1;
 				}
@@ -120,7 +120,7 @@ void parse_options(int argc, char **argv) {
 				break;
 			case 'v':
 				print_version();
-				exit(0);
+				exit(EXIT_SUCCESS);
 			case 'Z':
 				_options.scalemode = SCALE_ZOOM;
 				_options.zoom = 1.0;
@@ -130,7 +130,7 @@ void parse_options(int argc, char **argv) {
 				if (!sscanf(optarg, "%d", &t) || t <= 0) {
 					fprintf(stderr, "sxiv: invalid argument for option -z: %s\n",
 					        optarg);
-					exit(1);
+					exit(EXIT_FAILURE);
 				}
 				_options.zoom = (float) t / 100.0;
 				break;

util.c

@@ -87,7 +87,7 @@ void die(const char* fmt, ...) {
 	va_end(args);
 
 	cleanup();
-	exit(1);
+	exit(EXIT_FAILURE);
 }
 
 ssize_t get_line(char **buf, size_t *n, FILE *stream) {