coreutils/m4/uintptr_t.m4

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# uintptr_t.m4 serial 3
# Copyright (C) 2004 Free Software Foundation, Inc.
# This file is free software; the Free Software Foundation
# gives unlimited permission to copy and/or distribute it,
# with or without modifications, as long as this notice is preserved.
# Written by Paul Eggert.
AC_DEFUN([gl_AC_TYPE_UINTPTR_T],
[
AC_CACHE_CHECK([for uintptr_t], gl_cv_c_uintptr_t,
[gl_cv_c_uintptr_t=no
for ac_type in "uintptr_t" "unsigned int" \
"unsigned long int" "unsigned long long int"; do
AC_COMPILE_IFELSE(
[AC_LANG_BOOL_COMPILE_TRY(
[AC_INCLUDES_DEFAULT],
[[sizeof (void *) <= sizeof (uintptr_t)]])],
[gl_cv_c_uintptr_t=$ac_type])
test $gl_cv_c_uintptr_t != no && break
done])
case $gl_cv_c_uintptr_t in
no|uintptr_t) ;;
*)
AC_DEFINE_UNQUOTED(uintptr_t, $gl_cv_c_uintptr_t,
[Define to the type of a unsigned integer type wide enough to
hold a pointer, if such a type exists.])
;;
esac
dnl Check whether UINTPTR_MAX is defined, not whether it has the
dnl right value. Alas, Solaris 8 defines it to empty!
dnl Applications should use (uintptr_t) -1 rather than UINTPTR_MAX.
AC_CACHE_CHECK([for UINTPTR_MAX], gl_cv_c_uintptr_max,
[AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM(
[AC_INCLUDES_DEFAULT],
[[#ifndef UINTPTR_MAX
error: UINTPTR_MAX is not defined.
#endif]])],
[gl_cv_c_uintptr_max=yes],
[gl_cv_c_uintptr_max=no])])
case $gl_cv_c_uintptr_max,$gl_cv_c_uintptr_t in
yes,*) ;;
*,no) ;;
*)
AC_DEFINE(UINTPTR_MAX, ((uintptr_t) -1),
[Define to its maximum value if an unsigned integer type wide enough
to hold a pointer exists and the standard includes do not define
UINTPTR_MAX.])
;;
esac
])