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Annotation of embedaddon/expat/conftools/ac_c_bigendian_cross.m4, revision 1.1

1.1     ! misho       1: dnl @synopsis AC_C_BIGENDIAN_CROSS
        !             2: dnl
        !             3: dnl Check endianess even when crosscompiling
        !             4: dnl (partially based on the original AC_C_BIGENDIAN).
        !             5: dnl
        !             6: dnl The implementation will create a binary, and instead of running
        !             7: dnl the binary it will be grep'ed for some symbols that will look
        !             8: dnl different for different endianess of the binary.
        !             9: dnl
        !            10: dnl @version $Id: ac_c_bigendian_cross.m4,v 1.2 2001/10/01 20:03:13 fdrake Exp $
        !            11: dnl @author Guido Draheim <guidod@gmx.de>
        !            12: dnl
        !            13: AC_DEFUN([AC_C_BIGENDIAN_CROSS],
        !            14: [AC_CACHE_CHECK(whether byte ordering is bigendian, ac_cv_c_bigendian,
        !            15: [ac_cv_c_bigendian=unknown
        !            16: # See if sys/param.h defines the BYTE_ORDER macro.
        !            17: AC_TRY_COMPILE([#include <sys/types.h>
        !            18: #include <sys/param.h>], [
        !            19: #if !BYTE_ORDER || !BIG_ENDIAN || !LITTLE_ENDIAN
        !            20:  bogus endian macros
        !            21: #endif], [# It does; now see whether it defined to BIG_ENDIAN or not.
        !            22: AC_TRY_COMPILE([#include <sys/types.h>
        !            23: #include <sys/param.h>], [
        !            24: #if BYTE_ORDER != BIG_ENDIAN
        !            25:  not big endian
        !            26: #endif], ac_cv_c_bigendian=yes, ac_cv_c_bigendian=no)])
        !            27: if test $ac_cv_c_bigendian = unknown; then
        !            28: AC_TRY_RUN([main () {
        !            29:   /* Are we little or big endian?  From Harbison&Steele.  */
        !            30:   union
        !            31:   {
        !            32:     long l;
        !            33:     char c[sizeof (long)];
        !            34:   } u;
        !            35:   u.l = 1;
        !            36:   exit (u.c[sizeof (long) - 1] == 1);
        !            37: }], ac_cv_c_bigendian=no, ac_cv_c_bigendian=yes,
        !            38: [ echo $ac_n "cross-compiling... " 2>&AC_FD_MSG ])
        !            39: fi])
        !            40: if test $ac_cv_c_bigendian = unknown; then
        !            41: AC_MSG_CHECKING(to probe for byte ordering)
        !            42: [
        !            43: cat >conftest.c <<EOF
        !            44: short ascii_mm[] = { 0x4249, 0x4765, 0x6E44, 0x6961, 0x6E53, 0x7953, 0 };
        !            45: short ascii_ii[] = { 0x694C, 0x5454, 0x656C, 0x6E45, 0x6944, 0x6E61, 0 };
        !            46: void _ascii() { char* s = (char*) ascii_mm; s = (char*) ascii_ii; }
        !            47: short ebcdic_ii[] = { 0x89D3, 0xE3E3, 0x8593, 0x95C5, 0x89C4, 0x9581, 0 };
        !            48: short ebcdic_mm[] = { 0xC2C9, 0xC785, 0x95C4, 0x8981, 0x95E2, 0xA8E2, 0 };
        !            49: void _ebcdic() { char* s = (char*) ebcdic_mm; s = (char*) ebcdic_ii; }
        !            50: int main() { _ascii (); _ebcdic (); return 0; }
        !            51: EOF
        !            52: ] if test -f conftest.c ; then
        !            53:      if ${CC-cc} -c conftest.c -o conftest.o && test -f conftest.o ; then
        !            54:         if test `grep -l BIGenDianSyS conftest.o` ; then
        !            55:            echo $ac_n ' big endian probe OK, ' 1>&AC_FD_MSG
        !            56:            ac_cv_c_bigendian=yes
        !            57:         fi
        !            58:         if test `grep -l LiTTleEnDian conftest.o` ; then
        !            59:            echo $ac_n ' little endian probe OK, ' 1>&AC_FD_MSG
        !            60:            if test $ac_cv_c_bigendian = yes ; then
        !            61:             ac_cv_c_bigendian=unknown;
        !            62:            else
        !            63:             ac_cv_c_bigendian=no
        !            64:            fi
        !            65:         fi
        !            66:         echo $ac_n 'guessing bigendian ...  ' >&AC_FD_MSG
        !            67:      fi
        !            68:   fi
        !            69: AC_MSG_RESULT($ac_cv_c_bigendian)
        !            70: fi
        !            71: if test $ac_cv_c_bigendian = yes; then
        !            72:   AC_DEFINE(WORDS_BIGENDIAN, 1, [whether byteorder is bigendian])
        !            73:   BYTEORDER=4321
        !            74: else
        !            75:   BYTEORDER=1234
        !            76: fi
        !            77: AC_DEFINE_UNQUOTED(BYTEORDER, $BYTEORDER, [1234 = LIL_ENDIAN, 4321 = BIGENDIAN])
        !            78: if test $ac_cv_c_bigendian = unknown; then
        !            79:   AC_MSG_ERROR(unknown endianess - sorry, please pre-set ac_cv_c_bigendian)
        !            80: fi
        !            81: ])