c_cpp/etc/calc/have_offscl.c

   1 /*
   2  * have_offscl - determine if we have a scalar off_t element
   3  *
   4  * Copyright (C) 1999  Landon Curt Noll
   5  *
   6  * Calc is open software; you can redistribute it and/or modify it under
   7  * the terms of the version 2.1 of the GNU Lesser General Public License
   8  * as published by the Free Software Foundation.
   9  *
  10  * Calc is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  12  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General
  13  * Public License for more details.
  14  *
  15  * A copy of version 2.1 of the GNU Lesser General Public License is
  16  * distributed with calc under the filename COPYING-LGPL.  You should have
  17  * received a copy with calc; if not, write to Free Software Foundation, Inc.
  18  * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  19  *
  20  * @(#) $Revision: 30.2 $
  21  * @(#) $Id: have_offscl.c,v 30.2 2008/04/15 21:17:57 chongo Exp $
  22  * @(#) $Source: /usr/local/src/bin/calc/RCS/have_offscl.c,v $
  23  *
  24  * Under source code control:   1996/07/13 12:57:22
  25  * File existed as early as:    1996
  26  *
  27  * chongo <was here> /\oo/\     http://www.isthe.com/chongo/
  28  * Share and enjoy!  :-)        http://www.isthe.com/chongo/tech/comp/calc/
  29  */
  30
  31 /*
  32  * usage:
  33  *      have_offscl
  34  *
  35  * On some systems, off_t is a scalar value on which one can perform
  36  * arithmetic operations, assignments and comparisons.  On some systems
  37  * off_t is some sort of union or struct which must be converted into
  38  * a ZVALUE in order to perform arithmetic operations, assignments and
  39  * comparisons.
  40  *
  41  *
  42  * This prog outputs several defines:
  43  *
  44  *      HAVE_OFF_T_SCALAR
  45  *              defined ==> ok to perform arithmetic ops, = and comparisons
  46  *              undefined ==> convert to ZVALUE first
  47  */
  48
  49
  50 #include <stdio.h>
  51 #include <sys/types.h>
  52 #include <sys/stat.h>
  53
  54 int
  55 main(void)
  56 {
  57 #if !defined(OFF_T_NON_SCALAR)
  58         off_t value;    /* an off_t to perform arithmatic on */
  59         off_t value2;   /* an off_t to perform arithmatic on */
  60
  61         /*
  62          * do some math opts on an off_t
  63          */
  64         value = (off_t)getpid();
  65         value2 = (off_t)-1;
  66         if (value > (off_t)1) {
  67                 --value;
  68         }
  69 #if !defined(_WIN32)
  70         if (value <= (off_t)getppid()) {
  71                 --value;
  72         }
  73 #endif
  74         if (value == value2) {
  75                 value += value2;
  76         }
  77         value <<= 1;
  78         if (!value) {
  79                 printf("/* something for the off_t to do */\n");
  80         }
  81
  82         /*
  83          * report off_t as a scalar
  84          */
  85         printf("#undef HAVE_OFF_T_SCALAR\n");
  86         printf("#define HAVE_OFF_T_SCALAR /* off_t is a simple value */\n");
  87 #else
  88         printf("#undef HAVE_OFF_T_SCALAR /* off_t is not a simple value */\n");
  89 #endif
  90         /* exit(0); */
  91         return 0;
  92 }