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 #include <stdlib.h>
  22
  23 int main (int argc, char *argv[]) {
  24     int foo = 0x20212223;
  25     char *bar = (char *) &foo;
  26     switch(*bar) {
  27     case ' ':
  28         printf(" :big-endian");
  29         break;
  30     case '#':
  31         printf(" :little-endian");
  32         break;
  33     default:
  34         /* FIXME: How do we do sane error processing in Unix?  This
  35            program will be called from a script, in a manner somewhat
  36            like:
  37
  38                tools-for-build/determine-endianness >> $ltf
  39
  40            but what if we have a too-smart C compiler that actually
  41            gets us down to this branch?  I suppose that if we have a C
  42            compiler that is that smart, we're doomed to miscompile the
  43            runtime anyway, so we won't get here.  Still, it might be
  44            good to have "set -e" in the various scripts so that we can
  45            exit with an error here and have it be caught by the build
  46            tools.  -- CSR, 2002-11-24
  47         */
  48         exit(1);
  49     }
  50     exit(0);
  51 }