retval(1)

.gitignore

@@ -5,9 +5,12 @@ bin/lowercase
 bin/nonzero
 bin/nutshell
 bin/pscat
+bin/retval
 bin/rldecode
 bin/rlencode
 bin/roll
+bin/roll_stdio
+bin/rot13
 bin/simexec
 bin/sleep
 bin/str

Makefile

@@ -33,6 +33,7 @@ cleanprograms:
 	$(RM) bin/str
 	$(RM) bin/substitute
 	$(RM) bin/sysexits
+	$(RM) bin/retval
 	$(RM) bin/rldecode
 	$(RM) bin/rlencode
 	$(RM) bin/roll
@@ -99,16 +100,22 @@ pscat.o: libio src/pscat.c
 pscat: libio pscat.o
 	$(CC) $(CFLAGS) -o bin/pscat build/libio.o build/pscat.o
 
+retval.o: libio src/retval.c sysexits
+	$(CC) $(CFLAGS) -c -o build/retval.o src/retval.c
+
+retval: libio retval.o
+	$(CC) $(CFLAGS) -o bin/retval build/retval.o build/libio.o
+
 roll.o: lib/libio.h src/roll.c sysexits
 	$(CC) $(CFLAGS) -c -o build/roll.o src/roll.c
 
-roll: libio sysexits roll.o
+roll: libio roll.o
 	$(CC) $(CFLAGS) -o bin/roll build/libio.o build/roll.o
 
 roll_stdio.o: lib/libio.h src/roll.c sysexits
 	$(CC) $(CFLAGS) -c -DUSE_STDIO -o build/roll_stdio.o src/roll.c
 
-roll_stdio: libio sysexits roll_stdio.o
+roll_stdio: libio roll_stdio.o
 	$(CC) $(CFLAGS) -o bin/roll_stdio build/libio.o build/roll_stdio.o
 
 rot13.o: libio sysexits src/rot13.c

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;
 }