retval(1)

src/retval.c

@@ -1,24 +1,25 @@
-#include <ascii.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <sysexits.h>
-#include "libstr.h"
-#include "noargvzero.h"
+#include <ctype.h> /* isdigit(3) */
+#include <sysexits.h> /* EX_USAGE */
+#include <unistd.h> /* write(2) */
+#include "libio.h" /* fdprint(3), parse_uint(3) */
+
+static char *program_name = "retval";
 
 int main(int argc, char *argv[]){
-	int retval;
+	unsigned int s;
 
-	NOARGVZERO(argv);
-
-	if(argv[1] == NULL){
-		fprintf(stderr, "Usage: %s [exit code]\n", argv[0]);
+	if(argc < 2){
+usage:		write(2, "Usage: ", 7);
+		fdprint(2, argv[0] == NULL ? program_name : argv[0]);
+		write(2, " [status]\n", 10);
 		return EX_USAGE;
 	}
 
-	if(strint(argv[1], &retval, ASCII_DIGITS_DECIMAL_UPPER) == NULL){
-		fprintf(stderr, "%s: %s: Not an integer\n", argv[0], argv[1]);
-		return EX_USAGE;
-	}
+	for(s = 0; argv[1][s] != '\0'; ++s)
+		if(!isdigit(argv[1][s]))
+			goto usage;
 
-	return retval;
+	s = parse_uint(argv[1]);
+
+	return s;
 }