Refactor tty(1) code and manpage

README

@@ -71,7 +71,7 @@ The following tools are implemented ('*' == finished, '#' == UTF-8 support,
 =  touch           no                              -r
 #* tr              yes                             none
 =* true            yes                             none
-=  tty             yes                             none
+=* tty             yes                             none
 =  uname           yes                             none
 #  unexpand        yes                             none
 =  uniq            no                              -f, -s

tty.1

@@ -1,4 +1,4 @@
-.Dd January 30, 2015
+.Dd February 7, 2015
 .Dt TTY 1
 .Os sbase
 .Sh NAME
@@ -8,9 +8,21 @@
 .Nm
 .Sh DESCRIPTION
 .Nm
-prints the name of the terminal open on stdin.
+writes the name of the terminal open on stdin to stdout.
-.Pp
+.Sh EXIT STATUS
-The status code is 0 if stdin is a terminal, and 1 if not. If an error occurred
+.Bl -tag -width Ds
-the status code is 2.
+.It 0
+stdin is a terminal.
+.It 1
+stdin is not a terminal.
+.It > 1
+An error occurred.
+.El
 .Sh SEE ALSO
 .Xr ttyname 3
+.Sh STANDARDS
+The
+.Nm
+utility is compliant with the
+.St -p1003.1-2008
+specification.

tty.c

@@ -1,6 +1,5 @@
 /* See LICENSE file for copyright and license details. */
 #include <stdio.h>
-#include <stdlib.h>
 #include <unistd.h>
 
 #include "util.h"
@@ -23,5 +22,6 @@ main(int argc, char *argv[])
 
 	tty = ttyname(STDIN_FILENO);
 	puts(tty ? tty : "not a tty");
+
 	return tty ? 0 : 1;
 }