have_uid_t.c

/*
 * have_uid_t - Determine if we want or can support uid_t
 *
 * Copyright (C) 1999,2021  Landon Curt Noll
 *
 * Calc is open software; you can redistribute it and/or modify it under
 * the terms of the version 2.1 of the GNU Lesser General Public License
 * as published by the Free Software Foundation.
 *
 * Calc is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General
 * Public License for more details.
 *
 * A copy of version 2.1 of the GNU Lesser General Public License is
 * distributed with calc under the filename COPYING-LGPL.  You should have
 * received a copy with calc; if not, write to Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 * Under source code control:   1995/05/02 03:03:24
 * File existed as early as:    1995
 *
 * chongo <was here> /\oo/\     http://www.isthe.com/chongo/
 * Share and enjoy!  :-)        http://www.isthe.com/chongo/tech/comp/calc/
 */

/*
 * usage:
 *      have_uid_t
 *
 * Not all compilers support uid_t, so this may not compile on your system.
 *
 * This prog outputs several defines:
 *
 *      HAVE_UID_T
 *              defined ==> OK to use uid_t
 *              undefined ==> do not use uid_t
 */

#include <stdio.h>

#if !defined(HAVE_NO_UID_T)
#include "have_unistd.h"
#if defined(HAVE_UNISTD_H)
#include <unistd.h>
#endif
#include <pwd.h>
#include <sys/types.h>
#endif /* ! HAVE_NO_UID_T */


#include "banned.h"     /* include after system header <> includes */


int
main(void)
{
#if defined(HAVE_NO_UID_T)

        printf("#undef HAVE_UID_T /* no */\n");

#else /* HAVE_NO_UID_T */

        uid_t curds;
        extern uid_t geteuid();

        curds = geteuid();
        /* force curds to be used, but do not print much info about our UID */
        printf("/* geteuid() mod 2 == %ld */\n", ((long)curds) & 0x1);

        printf("#define HAVE_UID_T /* yes */\n");

#endif /* HAVE_NO_UID_T */

        /* exit(0); */
        return 0;
}