tty: use defines rather than constants

No obj-code changes.

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

diff --git a/coreutils/tty.c b/coreutils/tty.c
index 74a4ea3d606f0deebc770a8e8ecf87b8afa4989c..975ccdfaaa470224c4e24ef3fc7668524df567fa 100644 (file)
--- a/coreutils/tty.c
+++ b/coreutils/tty.c
@@ -7,8 +7,8 @@
  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  */
 
-/* BB_AUDIT SUSv3 compliant */
-/* http://www.opengroup.org/onlinepubs/007904975/utilities/tty.html */
+/* BB_AUDIT SUSv4 compliant */
+/* http://www.opengroup.org/onlinepubs/9699919799/utilities/tty.html */
 
 #include "libbb.h"
 
@@ -28,14 +28,14 @@ int tty_main(int argc, char **argv IF_NOT_INCLUDE_SUSv2(UNUSED_PARAM))
        /* gnu tty outputs a warning that it is ignoring all args. */
        bb_warn_ignoring_args(argc);
 
-       retval = 0;
+       retval = EXIT_SUCCESS;
 
-       s = xmalloc_ttyname(0);
+       s = xmalloc_ttyname(STDIN_FILENO);
        if (s == NULL) {
        /* According to SUSv3, ttyname can fail with EBADF or ENOTTY.
         * We know the file descriptor is good, so failure means not a tty. */
                s = "not a tty";
-               retval = 1;
+               retval = EXIT_FAILURE;
        }
        IF_INCLUDE_SUSv2(if (!silent) puts(s);)
        IF_NOT_INCLUDE_SUSv2(puts(s);)