portability and standards: add BSD-like err() and errx() functions

These are BSD functions.
- HaikuOS now compiles without having to use libbsd.
- Tested on SerenityOS (for fun), which doesn't have these functions (yet).
  With a small change to support wcwidth() sfeed works on SerenityOS.

1 files changed, 39 insertions, 0 deletions

diff --git a/util.c b/util.c
index e1ff9bd..c43bdfc 100644
--- a/util.c
+++ b/util.c
@@ -1,5 +1,6 @@
 #include <ctype.h>
 #include <errno.h>
+#include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -7,6 +8,44 @@
 
 #include "util.h"
 
+/* print to stderr, print error message of errno and exit().
+   Unlike BSD err() it does not prefix __progname */
+__dead void
+err(int exitstatus, const char *fmt, ...)
+{
+	va_list ap;
+	int saved_errno;
+
+	saved_errno = errno;
+
+	if (fmt) {
+		va_start(ap, fmt);
+		vfprintf(stderr, fmt, ap);
+		va_end(ap);
+		fprintf(stderr, ": ");
+	}
+	fprintf(stderr, "%s\n", strerror(saved_errno));
+
+	exit(exitstatus);
+}
+
+/* print to stderr and exit().
+   Unlike BSD errx() it does not prefix __progname */
+__dead void
+errx(int exitstatus, const char *fmt, ...)
+{
+	va_list ap;
+
+	if (fmt) {
+		va_start(ap, fmt);
+		vfprintf(stderr, fmt, ap);
+		va_end(ap);
+	}
+	fputs("\n", stderr);
+
+	exit(exitstatus);
+}
+
 /* check if string has a non-empty scheme / protocol part */
 int
 uri_hasscheme(const char *s)