tools-for-build/determine-endianness.c

   1 /*
   2  * Test for the endianness of the target platform (needed for MIPS
   3  * support, at the very least, as systems with either endianness exist
   4  * in the wild).
   5  */
   6
   7 /*
   8  * This software is part of the SBCL system. See the README file for
   9  * more information.
  10  *
  11  * While most of SBCL is derived from the CMU CL system, many
  12  * utilities for the build process (like this one) were written from
  13  * scratch after the fork from CMU CL.
  14  *
  15  * This software is in the public domain and is provided with
  16  * absolutely no warranty. See the COPYING and CREDITS files for
  17  * more information.
  18  */
  19
  20 #include <stdio.h>
  21
  22 int main (int argc, char *argv[]) {
  23     int foo = 0x20212223;
  24     char *bar = (char *) &foo;
  25     switch(*bar) {
  26     case ' ':
  27         /* Do nothing */
  28         break;
  29     case '#':
  30         printf(" :little-endian");
  31         break;
  32     default:
  33         /* FIXME: How do we do sane error processing in Unix?  This
  34            program will be called from a script, in a manner somewhat
  35            like:
  36
  37                tools-for-build/determine-endianness >> $ltf
  38
  39            but what if we have a too-smart C compiler that actually
  40            gets us down to this branch?  I suppose that if we have a C
  41            compiler that is that smart, we're doomed to miscompile the
  42            runtime anyway, so we won't get here.  Still, it might be
  43            good to have "set -e" in the various scripts so that we can
  44            exit with an error here and have it be caught by the build
  45            tools.  -- CSR, 2002-11-24
  46         */
  47         exit(1);
  48     }
  49     exit(0);
  50 }