# libguestfs
# Copyright (C) 2009-2025 Red Hat 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
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# 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.

dnl The C compiler environment.
dnl Define the host CPU architecture (defines 'host_cpu')
AC_CANONICAL_HOST

dnl Check for basic C environment.
AC_PROG_CC
AC_PROG_INSTALL
AC_PROG_CPP

AC_C_PROTOTYPES
test "x$U" != "x" && AC_MSG_ERROR([Compiler not ANSI compliant])

AM_PROG_CC_C_O

AC_ARG_ENABLE([werror],
    [AS_HELP_STRING([--enable-werror],
                    [turn on lots of GCC warnings (for developers)])],
     [case $enableval in
      yes|no) ;;
      *)      AC_MSG_ERROR([bad value $enableval for werror option]) ;;
      esac
      gcc_warnings=$enableval],
      [gcc_warnings=no]
)
WARN_CFLAGS="-Wall"
AC_SUBST([WARN_CFLAGS])
if test "x$gcc_warnings" = "xyes"; then
    WERROR_CFLAGS="-Werror"
fi
AC_SUBST([WERROR_CFLAGS])

# Provide a global place to set CFLAGS.  (Note that setting AM_CFLAGS
# is no use because it doesn't override target_CFLAGS).
#---
# Kill -fstrict-overflow which is a license for the C compiler to make
# dubious and often unsafe optimizations, in a time-wasting attempt to
# deal with CPU architectures that do not exist.
CFLAGS="$CFLAGS -fno-strict-overflow -Wno-strict-overflow"

dnl Check support for 64 bit file offsets.
AC_SYS_LARGEFILE

dnl Check sizeof long.
AC_CHECK_SIZEOF([long])

dnl Check if __attribute__((cleanup(...))) works.
dnl Set -Werror, otherwise gcc will only emit a warning for attributes
dnl that it doesn't understand.
acx_nbdkit_save_CFLAGS="${CFLAGS}"
CFLAGS="${CFLAGS} -Werror"
AC_MSG_CHECKING([if __attribute__((cleanup(...))) works with this compiler])
AC_COMPILE_IFELSE([
AC_LANG_SOURCE([[
#include <stdio.h>
#include <stdlib.h>

void
freep (void *ptr)
{
  exit (EXIT_SUCCESS);
}

void
test (void)
{
  __attribute__((cleanup(freep))) char *ptr = malloc (100);
}

int
main (int argc, char *argv[])
{
  test ();
  exit (EXIT_FAILURE);
}
]])
    ],[
    AC_MSG_RESULT([yes])
    AC_DEFINE([HAVE_ATTRIBUTE_CLEANUP],[1],[Define to 1 if '__attribute__((cleanup(...)))' works with this compiler.])
    ],[
    AC_MSG_ERROR(
['__attribute__((cleanup(...)))' does not work.

You may not be using a sufficiently recent version of GCC or CLANG, or
you may be using a C compiler which does not support this attribute,
or the configure test may be wrong.])])
dnl restore CFLAGS
CFLAGS="${acx_nbdkit_save_CFLAGS}"
