mirror of https://github.com/postgres/postgres
120 lines
3.4 KiB
Plaintext
120 lines
3.4 KiB
Plaintext
# Macros to detect C compiler features
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# $Header: /cvsroot/pgsql/config/c-compiler.m4,v 1.3 2000/08/29 09:36:37 petere Exp $
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# PGAC_C_SIGNED
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# -------------
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# Check if the C compiler understands signed types.
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AC_DEFUN([PGAC_C_SIGNED],
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[AC_CACHE_CHECK(for signed types, pgac_cv_c_signed,
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[AC_TRY_COMPILE([],
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[signed char c; signed short s; signed int i;],
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[pgac_cv_c_signed=yes],
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[pgac_cv_c_signed=no])])
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if test x"$pgac_cv_c_signed" = xno ; then
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AC_DEFINE(signed,, [Define empty if the C compiler does not understand signed types])
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fi])# PGAC_C_SIGNED
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# PGAC_C_VOLATILE
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# ---------------
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# Check if the C compiler understands `volatile'. Note that if it doesn't
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# then this will potentially break the program semantics.
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AC_DEFUN([PGAC_C_VOLATILE],
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[AC_CACHE_CHECK(for volatile, pgac_cv_c_volatile,
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[AC_TRY_COMPILE([],
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[extern volatile int i;],
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[pgac_cv_c_volatile=yes],
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[pgac_cv_c_volatile=no])])
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if test x"$pgac_cv_c_volatile" = xno ; then
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AC_DEFINE(volatile,, [Define empty if the C compiler does not understand `volatile'])
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fi])# PGAC_C_VOLATILE
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# PGAC_TYPE_64BIT_INT(TYPE)
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# -------------------------
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# Check if TYPE is a working 64 bit integer type. Set HAVE_TYPE_64 to
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# yes or no respectively, and define HAVE_TYPE_64 if yes.
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AC_DEFUN([PGAC_TYPE_64BIT_INT],
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[define([Ac_define], [translit([have_$1_64], [a-z *], [A-Z_P])])dnl
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define([Ac_cachevar], [translit([pgac_cv_type_$1_64], [ *], [_p])])dnl
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AC_CACHE_CHECK([whether $1 is 64 bits], [Ac_cachevar],
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[AC_TRY_RUN(
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[typedef $1 int64;
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/*
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* These are globals to discourage the compiler from folding all the
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* arithmetic tests down to compile-time constants.
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*/
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int64 a = 20000001;
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int64 b = 40000005;
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int does_int64_work()
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{
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int64 c,d;
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if (sizeof(int64) != 8)
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return 0; /* definitely not the right size */
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/* Do perfunctory checks to see if 64-bit arithmetic seems to work */
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c = a * b;
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d = (c + b) / b;
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if (d != a+1)
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return 0;
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return 1;
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}
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main() {
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exit(! does_int64_work());
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}],
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[Ac_cachevar=yes],
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[Ac_cachevar=no],
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[Ac_cachevar=no
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dnl We will do better here with Autoconf 2.50
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AC_MSG_WARN([64 bit arithmetic disabled when cross-compiling])])])
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Ac_define=$Ac_cachevar
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if test x"$Ac_cachevar" = xyes ; then
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AC_DEFINE(Ac_define,, [Set to 1 if `]$1[' is 64 bits])
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fi
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undefine([Ac_define])dnl
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undefine([Ac_cachevar])dnl
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])# PGAC_TYPE_64BIT_INT
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# PGAC_CHECK_ALIGNOF(TYPE)
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# ------------------------
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# Find the alignment requirement of the given type. Define the result
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# as ALIGNOF_TYPE. If cross-compiling, sizeof(type) is used as a
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# default assumption.
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#
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# This is modeled on the standard autoconf macro AC_CHECK_SIZEOF.
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# That macro never got any points for style.
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AC_DEFUN([PGAC_CHECK_ALIGNOF],
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[changequote(<<, >>)dnl
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dnl The name to #define.
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define(<<AC_TYPE_NAME>>, translit(alignof_$1, [a-z *], [A-Z_P]))dnl
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dnl The cache variable name.
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define(<<AC_CV_NAME>>, translit(pgac_cv_alignof_$1, [ *], [_p]))dnl
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changequote([, ])dnl
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AC_MSG_CHECKING(alignment of $1)
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AC_CACHE_VAL(AC_CV_NAME,
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[AC_TRY_RUN([#include <stdio.h>
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struct { char filler; $1 field; } mystruct;
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main()
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{
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FILE *f=fopen("conftestval", "w");
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if (!f) exit(1);
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fprintf(f, "%d\n", ((char*) & mystruct.field) - ((char*) & mystruct));
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exit(0);
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}], AC_CV_NAME=`cat conftestval`,
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AC_CV_NAME='sizeof($1)',
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AC_CV_NAME='sizeof($1)')])dnl
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AC_MSG_RESULT($AC_CV_NAME)
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AC_DEFINE_UNQUOTED(AC_TYPE_NAME, $AC_CV_NAME, [The alignment requirement of a `]$1['])
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undefine([AC_TYPE_NAME])dnl
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undefine([AC_CV_NAME])dnl
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])# PGAC_CHECK_ALIGNOF
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