From b7b5462bde6ed791c19ea5a918cb4ff1dd532175 Mon Sep 17 00:00:00 2001
From: Hiltjo Posthuma <hiltjo@codemadness.org>
Date: Mon, 4 May 2015 22:06:17 +0200
Subject: [PATCH 3/4] util: die(): print errno if last character is ':'

... and make use of it for some functions.
---
 dwm.c  |  8 ++++----
 util.c | 15 +++++++++++----
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/dwm.c b/dwm.c
index f447f60..1446800 100644
--- a/dwm.c
+++ b/dwm.c
@@ -632,7 +632,7 @@ createmon(void) {
 	Monitor *m;
 
 	if(!(m = (Monitor *)calloc(1, sizeof(Monitor))))
-		die("fatal: could not malloc() %u bytes\n", sizeof(Monitor));
+		die("fatal: could not malloc() %u bytes:", sizeof(Monitor));
 	m->tagset[0] = m->tagset[1] = 1;
 	m->mfact = mfact;
 	m->nmaster = nmaster;
@@ -1011,7 +1011,7 @@ manage(Window w, XWindowAttributes *wa) {
 	XWindowChanges wc;
 
 	if(!(c = calloc(1, sizeof(Client))))
-		die("fatal: could not malloc() %u bytes\n", sizeof(Client));
+		die("fatal: could not malloc() %u bytes:", sizeof(Client));
 	c->win = w;
 	updatetitle(c);
 	if(XGetTransientForHint(dpy, w, &trans) && (t = wintoclient(trans))) {
@@ -1575,7 +1575,7 @@ showhide(Client *c) {
 void
 sigchld(int unused) {
 	if(signal(SIGCHLD, sigchld) == SIG_ERR)
-		die("Can't install SIGCHLD handler");
+		die("Can't install SIGCHLD handler:");
 	while(0 < waitpid(-1, NULL, WNOHANG));
 }
 
@@ -1792,7 +1792,7 @@ updategeom(void) {
 		for(n = 0, m = mons; m; m = m->next, n++);
 		/* only consider unique geometries as separate screens */
 		if(!(unique = (XineramaScreenInfo *)malloc(sizeof(XineramaScreenInfo) * nn)))
-			die("fatal: could not malloc() %u bytes\n", sizeof(XineramaScreenInfo) * nn);
+			die("fatal: could not malloc() %u bytes:", sizeof(XineramaScreenInfo) * nn);
 		for(i = 0, j = 0; i < nn; i++)
 			if(isuniquegeom(unique, j, &info[i]))
 				memcpy(&unique[j++], &info[i], sizeof(XineramaScreenInfo));
diff --git a/util.c b/util.c
index 51acd1a..78d3035 100644
--- a/util.c
+++ b/util.c
@@ -2,16 +2,23 @@
 #include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 
 #include "util.h"
 
 void
-die(const char *errstr, ...) {
+die(const char *fmt, ...) {
 	va_list ap;
 
-	va_start(ap, errstr);
-	vfprintf(stderr, errstr, ap);
+	va_start(ap, fmt);
+	vfprintf(stderr, fmt, ap);
 	va_end(ap);
-	exit(EXIT_FAILURE);
+
+	if (fmt[0] && fmt[strlen(fmt)-1] == ':') {
+		fputc(' ', stderr);
+		perror(NULL);
+	}
+
+	exit(1);
 }
 
-- 
2.3.7