types.m4

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# This file is part of Autoconf.			-*- Autoconf -*-
# Type related macros: existence, sizeof, and structure members.
#
# Copyright (C) 2000, 2001, 2002, 2004, 2005, 2006 Free Software
# Foundation, Inc.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
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#
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# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301, USA.
#
# As a special exception, the Free Software Foundation gives unlimited
# permission to copy, distribute and modify the configure scripts that
# are the output of Autoconf.  You need not follow the terms of the GNU
# General Public License when using or distributing such scripts, even
# though portions of the text of Autoconf appear in them.  The GNU
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#
# Certain portions of the Autoconf source text are designed to be copied
# (in certain cases, depending on the input) into the output of
# Autoconf.  We call these the "data" portions.  The rest of the Autoconf
# source text consists of comments plus executable code that decides which
# of the data portions to output in any given case.  We call these
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# to the GPL from your modified version.
#
# Written by David MacKenzie, with help from
# Franc,ois Pinard, Karl Berry, Richard Pixley, Ian Lance Taylor,
# Roland McGrath, Noah Friedman, david d zuhn, and many others.


## ---------------- ##
## Type existence.  ##
## ---------------- ##

# ---------------- #
# General checks.  #
# ---------------- #

# Up to 2.13 included, Autoconf used to provide the macro
#
#    AC_CHECK_TYPE(TYPE, DEFAULT)
#
# Since, it provides another version which fits better with the other
# AC_CHECK_ families:
#
#    AC_CHECK_TYPE(TYPE,
#		   [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND],
#		   [INCLUDES = DEFAULT-INCLUDES])
#
# In order to provide backward compatibility, the new scheme is
# implemented as _AC_CHECK_TYPE_NEW, the old scheme as _AC_CHECK_TYPE_OLD,
# and AC_CHECK_TYPE branches to one or the other, depending upon its
# arguments.



# _AC_CHECK_TYPE_NEW(TYPE,
#		     [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND],
#		     [INCLUDES = DEFAULT-INCLUDES])
# ------------------------------------------------------------
# Check whether the type TYPE is supported by the system, maybe via the
# the provided includes.  This macro implements the former task of
# AC_CHECK_TYPE, with one big difference though: AC_CHECK_TYPE was
# grepping in the headers, which, BTW, led to many problems until the
# extended regular expression was correct and did not given false positives.
# It turned out there are even portability issues with egrep...
#
# The most obvious way to check for a TYPE is just to compile a variable
# definition:
#
#	  TYPE my_var;
#
# Unfortunately this does not work for const qualified types in C++,
# where you need an initializer.  So you think of
#
#	  TYPE my_var = (TYPE) 0;
#
# Unfortunately, again, this is not valid for some C++ classes.
#
# Then you look for another scheme.  For instance you think of declaring
# a function which uses a parameter of type TYPE:
#
#	  int foo (TYPE param);
#
# but of course you soon realize this does not make it with K&R
# compilers.  And by no ways you want to
#
#	  int foo (param)
#	    TYPE param
#	  { ; }
#
# since this time it's C++ who is not happy.
#
# Don't even think of the return type of a function, since K&R cries
# there too.  So you start thinking of declaring a *pointer* to this TYPE:
#
#	  TYPE *p;
#
# but you know fairly well that this is legal in C for aggregates which
# are unknown (TYPE = struct does-not-exist).
#
# Then you think of using sizeof to make sure the TYPE is really
# defined:
#
#	  sizeof (TYPE);
#
# But this succeeds if TYPE is a variable: you get the size of the
# variable's type!!!
#
# This time you tell yourself the last two options *together* will make
# it.  And indeed this is the solution invented by Alexandre Oliva.
#
# Also note that we use
#
#	  if (sizeof (TYPE))
#
# to `read' sizeof (to avoid warnings), while not depending on its type
# (not necessarily size_t etc.).  Equally, instead of defining an unused
# variable, we just use a cast to avoid warnings from the compiler.
# Suggested by Paul Eggert.
#
# Now, the next issue is that C++ disallows defining types inside casts
# and inside `sizeof()', but we would like to allow unnamed structs, for
# use inside AC_CHECK_SIZEOF, for example.  So we create a typedef of the
# new type.  Note that this does not obviate the need for the other
# constructs in general.
m4_define([_AC_CHECK_TYPE_NEW],
[AS_VAR_PUSHDEF([ac_Type], [ac_cv_type_$1])dnl
AC_CACHE_CHECK([for $1], ac_Type,
[AC_COMPILE_IFELSE([AC_LANG_PROGRAM([AC_INCLUDES_DEFAULT([$4])
typedef $1 ac__type_new_;],
[if ((ac__type_new_ *) 0)
  return 0;
if (sizeof (ac__type_new_))
  return 0;])],
		   [AS_VAR_SET(ac_Type, yes)],
		   [AS_VAR_SET(ac_Type, no)])])
AS_IF([test AS_VAR_GET(ac_Type) = yes], [$2], [$3])[]dnl
AS_VAR_POPDEF([ac_Type])dnl
])# _AC_CHECK_TYPE_NEW


# AC_CHECK_TYPES(TYPES,
#		 [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND],
#		 [INCLUDES = DEFAULT-INCLUDES])
# --------------------------------------------------------
# TYPES is an m4 list.  There are no ambiguities here, we mean the newer
# AC_CHECK_TYPE.
AC_DEFUN([AC_CHECK_TYPES],
[m4_foreach([AC_Type], [$1],
  [_AC_CHECK_TYPE_NEW(AC_Type,
		      [AC_DEFINE_UNQUOTED(AS_TR_CPP(HAVE_[]AC_Type), 1,
					  [Define to 1 if the system has the
					   type `]AC_Type['.])
$2],
		      [$3],
		      [$4])])])


# _AC_CHECK_TYPE_OLD(TYPE, DEFAULT)
# ---------------------------------
# FIXME: This is an extremely badly chosen name, since this
# macro actually performs an AC_REPLACE_TYPE.  Some day we
# have to clean this up.
m4_define([_AC_CHECK_TYPE_OLD],
[_AC_CHECK_TYPE_NEW([$1],,
   [AC_DEFINE_UNQUOTED([$1], [$2],
		       [Define to `$2' if <sys/types.h> does not define.])])dnl
])# _AC_CHECK_TYPE_OLD


# _AC_CHECK_TYPE_REPLACEMENT_TYPE_P(STRING)
# -----------------------------------------
# Return `1' if STRING seems to be a builtin C/C++ type, i.e., if it
# starts with `_Bool', `bool', `char', `double', `float', `int',
# `long', `short', `signed', or `unsigned' followed by characters
# that are defining types.
# Because many people have used `off_t' and `size_t' too, they are added
# for better common-useward backward compatibility.
m4_define([_AC_CHECK_TYPE_REPLACEMENT_TYPE_P],
[m4_bmatch([$1],
	  [^\(_Bool\|bool\|char\|double\|float\|int\|long\|short\|\(un\)?signed\|[_a-zA-Z][_a-zA-Z0-9]*_t\)[][_a-zA-Z0-9() *]*$],
	  1, 0)dnl
])# _AC_CHECK_TYPE_REPLACEMENT_TYPE_P


# _AC_CHECK_TYPE_MAYBE_TYPE_P(STRING)
# -----------------------------------
# Return `1' if STRING looks like a C/C++ type.
m4_define([_AC_CHECK_TYPE_MAYBE_TYPE_P],
[m4_bmatch([$1], [^[_a-zA-Z0-9 ]+\([_a-zA-Z0-9() *]\|\[\|\]\)*$],
	  1, 0)dnl
])# _AC_CHECK_TYPE_MAYBE_TYPE_P


# AC_CHECK_TYPE(TYPE, DEFAULT)
#  or
# AC_CHECK_TYPE(TYPE,
#		[ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND],
#		[INCLUDES = DEFAULT-INCLUDES])
# -------------------------------------------------------
#
# Dispatch respectively to _AC_CHECK_TYPE_OLD or _AC_CHECK_TYPE_NEW.
# 1. More than two arguments	     => NEW
# 2. $2 seems to be replacement type => OLD
#    See _AC_CHECK_TYPE_REPLACEMENT_TYPE_P for `replacement type'.
# 3. $2 seems to be a type	     => NEW plus a warning
# 4. default			     => NEW
AC_DEFUN([AC_CHECK_TYPE],
[m4_if($#, 3,
	 [_AC_CHECK_TYPE_NEW($@)],
       $#, 4,
	 [_AC_CHECK_TYPE_NEW($@)],
       _AC_CHECK_TYPE_REPLACEMENT_TYPE_P([$2]), 1,
	 [_AC_CHECK_TYPE_OLD($@)],
       _AC_CHECK_TYPE_MAYBE_TYPE_P([$2]), 1,
	 [AC_DIAGNOSE([syntax],
		    [$0: assuming `$2' is not a type])_AC_CHECK_TYPE_NEW($@)],
       [_AC_CHECK_TYPE_NEW($@)])[]dnl
])# AC_CHECK_TYPE



# ---------------------------- #
# Types that must be checked.  #
# ---------------------------- #

AN_IDENTIFIER([ptrdiff_t], [AC_CHECK_TYPES])


# ----------------- #
# Specific checks.  #
# ----------------- #

# AC_TYPE_GETGROUPS
# -----------------
AC_DEFUN([AC_TYPE_GETGROUPS],
[AC_REQUIRE([AC_TYPE_UID_T])dnl
AC_CACHE_CHECK(type of array argument to getgroups, ac_cv_type_getgroups,
[AC_RUN_IFELSE([AC_LANG_SOURCE(
[[/* Thanks to Mike Rendell for this test.  */
]AC_INCLUDES_DEFAULT[
#define NGID 256
#undef MAX
#define MAX(x, y) ((x) > (y) ? (x) : (y))

int
main ()
{
  gid_t gidset[NGID];
  int i, n;
  union { gid_t gval; long int lval; }  val;

  val.lval = -1;
  for (i = 0; i < NGID; i++)
    gidset[i] = val.gval;
  n = getgroups (sizeof (gidset) / MAX (sizeof (int), sizeof (gid_t)) - 1,
		 gidset);
  /* Exit non-zero if getgroups seems to require an array of ints.  This
     happens when gid_t is short int but getgroups modifies an array
     of ints.  */
  return n > 0 && gidset[n] != val.gval;
}]])],
	       [ac_cv_type_getgroups=gid_t],
	       [ac_cv_type_getgroups=int],
	       [ac_cv_type_getgroups=cross])
if test $ac_cv_type_getgroups = cross; then
  dnl When we can't run the test program (we are cross compiling), presume
  dnl that <unistd.h> has either an accurate prototype for getgroups or none.
  dnl Old systems without prototypes probably use int.
  AC_EGREP_HEADER([getgroups.*int.*gid_t], unistd.h,
		  ac_cv_type_getgroups=gid_t, ac_cv_type_getgroups=int)
fi])
AC_DEFINE_UNQUOTED(GETGROUPS_T, $ac_cv_type_getgroups,
		   [Define to the type of elements in the array set by
		    `getgroups'. Usually this is either `int' or `gid_t'.])
])# AC_TYPE_GETGROUPS


# AU::AM_TYPE_PTRDIFF_T
# ---------------------
AU_DEFUN([AM_TYPE_PTRDIFF_T],
[AC_CHECK_TYPES(ptrdiff_t)])


# AC_TYPE_INTMAX_T
# -----------------
AC_DEFUN([AC_TYPE_INTMAX_T],
[
  AC_REQUIRE([AC_TYPE_LONG_LONG_INT])
  AC_CHECK_TYPE([intmax_t],
    [AC_DEFINE([HAVE_INTMAX_T], 1,
       [Define to 1 if the system has the type `intmax_t'.])],
    [test $ac_cv_type_long_long_int = yes \
       && ac_type='long long int' \
       || ac_type='long int'