From 94ee3156b7a22b02f8b21e6db3fcdf7d1ad51d0e Mon Sep 17 00:00:00 2001
From: Luke Shumaker <lukeshu@beefcake.parabola.nu>
Date: Wed, 16 May 2018 10:18:21 -0400
Subject: errusage

---
 src/cow-dedupe-range.c | 29 +++++++++++++++--------------
 1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/src/cow-dedupe-range.c b/src/cow-dedupe-range.c
index 33d62b0..bffa8f1 100644
--- a/src/cow-dedupe-range.c
+++ b/src/cow-dedupe-range.c
@@ -7,12 +7,19 @@
 #include <stdbool.h> /* for bool, true, false */
 #include <stdint.h>  /* for uint64_t */
 #include <stdio.h>   /* for printf(3gnu), fprintf(3p), stderr */
-#include <stdlib.h>  /* for strtoll(3p), calloc(3p), free(3p) */
+#include <stdlib.h>  /* for strtoll(3p), calloc(3p), free(3p), exit(3p), EXIT_SUCCESS */
 #include <string.h>  /* for strlen(3p) */
 #include <unistd.h>  /* for dup2(3p) */
 
 #include "dedupe-range.h" /* for dedupe_range, struct range */
 
+#define EXIT_INVALIDARGUMENT 2
+#define errusage(format, ...) do { \
+	error(0, 0, format, ## __VA_ARGS__); \
+	fprintf(stderr, "Try '%s --help' for more information.\n", program_invocation_name); \
+	exit(EXIT_INVALIDARGUMENT); \
+} while(0)
+
 bool atou64(const char *str, uint64_t *ret) {
 	assert(sizeof(uint64_t) <= sizeof(unsigned long long int));
 	if (!('0' <= str[0] && str[0] <= '9'))
@@ -59,24 +66,18 @@ int main(int argc, char *argv[]) {
 			break;
 		case 'h':
 			usage();
-			return 0;
+			return EXIT_SUCCESS;
 		case '?':
 			fprintf(stderr, "Try '%s --help' for more information.\n", program_invocation_name);
-			return 2;
+			return EXIT_INVALIDARGUMENT;
 		default:
 			assert(false);
 		}
 	}
-	if (argc - optind < 5) {
-		error(0, 0, "too few arguments");
-		fprintf(stderr, "Try '%s --help' for more information.\n", program_invocation_name);
-		return 2;
-	}
-	if ((argc - optind - 3) % 2 != 0) {
-		error(0, 0, "wrong number of arguments");
-		fprintf(stderr, "Try '%s --help' for more information.\n", program_invocation_name);
-		return 2;
-	}
+	if (argc - optind < 5)
+		errusage("too few arguments");
+	if ((argc - optind - 3) % 2 != 0)
+		errusage("wrong number of arguments");
 
 	struct range src;
 	src.filename = argv[optind];
@@ -97,5 +98,5 @@ int main(int argc, char *argv[]) {
 
 	dedupe_range(src, dsts);
 	free(dsts);
-	return 0;
+	return EXIT_SUCCESS;
 }
-- 
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