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emacs/m4/largefile.m4
Paul Eggert 4a8c8021cc Update from Gnulib by running admin/merge-gnulib 
* m4/wchar_t.m4: Remove; no longer needed.
2024-06-30 01:03:16 +01:00

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# largefile.m4
# serial 2
dnl Copyright 1992-1996, 1998-2024 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
# Enable large files on systems where this is not the default.
# Enable support for files on Linux file systems with 64-bit inode numbers.
# The following macro works around a problem in Autoconf's AC_FUNC_FSEEKO:
# It does not set _LARGEFILE_SOURCE=1 on HP-UX/ia64 32-bit, although this
# setting of _LARGEFILE_SOURCE is needed so that <stdio.h> declares fseeko
# and ftello in C++ mode as well.
# This problem occurs in Autoconf 2.71 and earlier, which lack AC_SYS_YEAR2038.
AC_DEFUN([gl_SET_LARGEFILE_SOURCE],
m4_ifndef([AC_SYS_YEAR2038], [[
AC_REQUIRE([AC_CANONICAL_HOST])
AC_FUNC_FSEEKO
case "$host_os" in
hpux*)
AC_DEFINE([_LARGEFILE_SOURCE], [1],
[Define to 1 to make fseeko visible on some hosts (e.g. glibc 2.2).])
;;
esac
]])
)
dnl Remove AC_SYS_YEAR2038_RECOMMENDED if unpatched Autoconf 2.72 or earlier.
dnl Autoconf 2.72 still uses -n32, which is not a C preprocessor option,
dnl and which was useful only on IRIX which is no longer supported.
dnl This should be fixed in Autoconf 2.73.
m4_ifdef([AC_SYS_YEAR2038_RECOMMENDED],
[m4_bmatch(m4_ifdef([_AC_SYS_LARGEFILE_OPTIONS],
[m4_defn([_AC_SYS_LARGEFILE_OPTIONS])],
["-n32"]),
["-n32"],
[m4_undefine([AC_SYS_YEAR2038_RECOMMENDED])])])
m4_ifndef([AC_SYS_YEAR2038_RECOMMENDED], [
# Fix up AC_SYS_YEAR2038_RECOMMENDED and related macros, even if
# unpatched Autoconf 2.72 or earlier. This code is taken from Autoconf master.
# _AC_SYS_YEAR2038_TEST_CODE
# --------------------------
# C code used to probe for time_t that can represent time points more
# than 2**31 - 1 seconds after the epoch. With the usual Unix epoch,
# these correspond to dates after 2038-01-18 22:14:07 +0000 (Gregorian),
# hence the name.
AC_DEFUN([_AC_SYS_YEAR2038_TEST_CODE],
[[
#include <time.h>
/* Check that time_t can represent 2**32 - 1 correctly. */
#define LARGE_TIME_T \\
((time_t) (((time_t) 1 << 30) - 1 + 3 * ((time_t) 1 << 30)))
int verify_time_t_range[(LARGE_TIME_T / 65537 == 65535
&& LARGE_TIME_T % 65537 == 0)
? 1 : -1];
]])
# _AC_SYS_YEAR2038_OPTIONS
# ------------------------
# List of known ways to enable support for large time_t. If you change
# this list you probably also need to change the AS_CASE at the end of
# _AC_SYS_YEAR2038_PROBE.
m4_define([_AC_SYS_YEAR2038_OPTIONS], m4_normalize(
["none needed"] dnl 64-bit and newer 32-bit Unix
["-D_TIME_BITS=64"] dnl glibc 2.34 with some 32-bit ABIs
["-D__MINGW_USE_VC2005_COMPAT"] dnl 32-bit MinGW
["-U_USE_32_BIT_TIME_T -D__MINGW_USE_VC2005_COMPAT"]
dnl 32-bit MinGW (misconfiguration)
))
# _AC_SYS_YEAR2038_PROBE
# ----------------------
# Subroutine of AC_SYS_YEAR2038. Probe for time_t that can represent
# time points more than 2**31 - 1 seconds after the epoch (dates after
# 2038-01-18, see above) and set the cache variable ac_cv_sys_year2038_opts
# to one of the values in the _AC_SYS_YEAR2038_OPTIONS list, or to
# "support not detected" if none of them worked. Then, set compilation
# options and #defines as necessary to enable large time_t support.
#
# Note that we do not test whether mktime, localtime, etc. handle
# large values of time_t correctly, as that would require use of
# AC_TRY_RUN. Note also that some systems only support large time_t
# together with large off_t.
#
# If you change this macro you may also need to change
# _AC_SYS_YEAR2038_OPTIONS.
AC_DEFUN([_AC_SYS_YEAR2038_PROBE],
[AC_CACHE_CHECK([for $CC option to support timestamps after 2038],
[ac_cv_sys_year2038_opts],
[ac_save_CPPFLAGS="$CPPFLAGS"
ac_opt_found=no
for ac_opt in _AC_SYS_YEAR2038_OPTIONS; do
AS_IF([test x"$ac_opt" != x"none needed"],
[CPPFLAGS="$ac_save_CPPFLAGS $ac_opt"])
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([_AC_SYS_YEAR2038_TEST_CODE])],
[ac_cv_sys_year2038_opts="$ac_opt"
ac_opt_found=yes])
test $ac_opt_found = no || break
done
CPPFLAGS="$ac_save_CPPFLAGS"
test $ac_opt_found = yes || ac_cv_sys_year2038_opts="support not detected"])
ac_have_year2038=yes
AS_CASE([$ac_cv_sys_year2038_opts],
["none needed"], [],
["support not detected"],
[ac_have_year2038=no],
["-D_TIME_BITS=64"],
[AC_DEFINE([_TIME_BITS], [64],
[Number of bits in time_t, on hosts where this is settable.])],
["-D__MINGW_USE_VC2005_COMPAT"],
[AC_DEFINE([__MINGW_USE_VC2005_COMPAT], [1],
[Define to 1 on platforms where this makes time_t a 64-bit type.])],
["-U_USE_32_BIT_TIME_T"*],
[AC_MSG_FAILURE(m4_text_wrap(
[the 'time_t' type is currently forced to be 32-bit.
It will stop working after mid-January 2038.
Remove _USE_32BIT_TIME_T from the compiler flags.],
[], [], [55]))],
[AC_MSG_ERROR(
[internal error: bad value for \$ac_cv_sys_year2038_opts])])
])
# _AC_SYS_YEAR2038_ENABLE
# -----------------------
# Depending on which of the YEAR2038 macros was used, add either an
# --enable-year2038 or a --disable-year2038 to
# the configure script. This is expanded very late and
# therefore there cannot be any code in the AC_ARG_ENABLE. The
# default value for 'enable_year2038' is emitted unconditionally
# because the generated code always looks at this variable.
m4_define([_AC_SYS_YEAR2038_ENABLE],
[m4_divert_text([DEFAULTS],
m4_provide_if([AC_SYS_YEAR2038],
[enable_year2038=yes],
[enable_year2038=no]))]dnl
[AC_ARG_ENABLE([year2038],
m4_provide_if([AC_SYS_YEAR2038],
[AS_HELP_STRING([--disable-year2038],
[don't support timestamps after 2038])],
[AS_HELP_STRING([--enable-year2038],
[support timestamps after 2038])]))])
# AC_SYS_YEAR2038
# ---------------
# Attempt to detect and activate support for large time_t.
# On systems where time_t is not always 64 bits, this probe can be
# skipped by passing the --disable-year2038 option to configure.
AC_DEFUN([AC_SYS_YEAR2038],
[AC_REQUIRE([AC_SYS_LARGEFILE])dnl
AS_IF([test "$enable_year2038,$ac_have_year2038,$cross_compiling" = yes,no,no],
[# If we're not cross compiling and 'touch' works with a large
# timestamp, then we can presume the system supports wider time_t
# *somehow* and we just weren't able to detect it. One common
# case that we deliberately *don't* probe for is a system that
# supports both 32- and 64-bit ABIs but only the 64-bit ABI offers
# wide time_t. (It would be inappropriate for us to override an
# intentional use of -m32.) Error out, demanding use of
# --disable-year2038 if this is intentional.
AS_IF([TZ=UTC0 touch -t 210602070628.15 conftest.time 2>/dev/null],
[AS_CASE([`TZ=UTC0 LC_ALL=C ls -l conftest.time 2>/dev/null`],
[*'Feb 7 2106'* | *'Feb 7 17:10'*],
[AC_MSG_FAILURE(m4_text_wrap(
[this system appears to support timestamps after mid-January 2038,
but no mechanism for enabling wide 'time_t' was detected.
Did you mean to build a 64-bit binary? (E.g., 'CC="${CC} -m64"'.)
To proceed with 32-bit time_t, configure with '--disable-year2038'.],
[], [], [55]))])])])])
# AC_SYS_YEAR2038_RECOMMENDED
# ---------------------------
# Same as AC_SYS_YEAR2038, but recommend support for large time_t.
# If we cannot find any way to make time_t capable of representing
# values larger than 2**31 - 1, error out unless --disable-year2038 is given.
AC_DEFUN([AC_SYS_YEAR2038_RECOMMENDED],
[AC_REQUIRE([AC_SYS_YEAR2038])dnl
AS_IF([test "$enable_year2038,$ac_have_year2038" = yes,no],
[AC_MSG_FAILURE(m4_text_wrap(
[could not enable timestamps after mid-January 2038.
This package recommends support for these later timestamps.
However, to proceed with signed 32-bit time_t even though it
will fail then, configure with '--disable-year2038'.],
[], [], [55]))])])
# _AC_SYS_LARGEFILE_TEST_CODE
# ---------------------------
# C code used to probe for large file support.
m4_define([_AC_SYS_LARGEFILE_TEST_CODE],
[@%:@include <sys/types.h>
@%:@ifndef FTYPE
@%:@ define FTYPE off_t
@%:@endif
/* Check that FTYPE can represent 2**63 - 1 correctly.
We can't simply define LARGE_FTYPE to be 9223372036854775807,
since some C++ compilers masquerading as C compilers
incorrectly reject 9223372036854775807. */
@%:@define LARGE_FTYPE (((FTYPE) 1 << 31 << 31) - 1 + ((FTYPE) 1 << 31 << 31))
int FTYPE_is_large[[(LARGE_FTYPE % 2147483629 == 721
&& LARGE_FTYPE % 2147483647 == 1)
? 1 : -1]];[]dnl
])
# Defined by Autoconf 2.71 and circa 2022 Gnulib unwisely depended on it.
m4_define([_AC_SYS_LARGEFILE_TEST_INCLUDES], [_AC_SYS_LARGEFILE_TEST_CODE])
# _AC_SYS_LARGEFILE_OPTIONS
# -------------------------
# List of known ways to enable support for large files. If you change
# this list you probably also need to change the AS_CASE at the end of
# _AC_SYS_LARGEFILE_PROBE.
m4_define([_AC_SYS_LARGEFILE_OPTIONS], m4_normalize(
["none needed"] dnl Most current systems
["-D_FILE_OFFSET_BITS=64"] dnl X/Open LFS spec
["-D_LARGE_FILES=1"] dnl 32-bit AIX 4.2.1+, 32-bit z/OS
))
# _AC_SYS_LARGEFILE_PROBE
# -----------------------
# Subroutine of AC_SYS_LARGEFILE. Probe for large file support and set
# the cache variable ac_cv_sys_largefile_opts to one of the values in
# the _AC_SYS_LARGEFILE_OPTIONS list, or to "support not detected" if
# none of the options in that list worked. Then, set compilation
# options and #defines as necessary to enable large file support.
#
# If large file support is not detected, the behavior depends on which of
# the top-level AC_SYS_LARGEFILE macros was used (see below).
#
# If you change this macro you may also need to change
# _AC_SYS_LARGEFILE_OPTIONS.
AC_DEFUN([_AC_SYS_LARGEFILE_PROBE],
[AC_CACHE_CHECK([for $CC option to support large files],
[ac_cv_sys_largefile_opts],
[ac_save_CPPFLAGS=$CPPFLAGS
ac_opt_found=no
for ac_opt in _AC_SYS_LARGEFILE_OPTIONS; do
AS_IF([test x"$ac_opt" != x"none needed"],
[CPPFLAGS="$ac_save_CPPFLAGS $ac_opt"])
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([_AC_SYS_LARGEFILE_TEST_CODE])],
[AS_IF([test x"$ac_opt" = x"none needed"],
[# GNU/Linux s390x and alpha need _FILE_OFFSET_BITS=64 for wide ino_t.
CPPFLAGS="$CPPFLAGS -DFTYPE=ino_t"
AC_COMPILE_IFELSE([], [],
[CPPFLAGS="$CPPFLAGS -D_FILE_OFFSET_BITS=64"
AC_COMPILE_IFELSE([], [ac_opt='-D_FILE_OFFSET_BITS=64'])])])
ac_cv_sys_largefile_opts=$ac_opt
ac_opt_found=yes])
test $ac_opt_found = no || break
done
CPPFLAGS=$ac_save_CPPFLAGS
dnl Gnulib implements large file support for native Windows, based on the
dnl variables WINDOWS_64_BIT_OFF_T, WINDOWS_64_BIT_ST_SIZE.
m4_ifdef([gl_LARGEFILE], [
AC_REQUIRE([AC_CANONICAL_HOST])
if test $ac_opt_found != yes; then
AS_CASE([$host_os],
[mingw* | windows*],
[ac_cv_sys_largefile_opts="supported through gnulib"
ac_opt_found=yes]
)
fi
])
test $ac_opt_found = yes || ac_cv_sys_largefile_opts="support not detected"])
ac_have_largefile=yes
AS_CASE([$ac_cv_sys_largefile_opts],
["none needed"], [],
["supported through gnulib"], [],
["support not detected"],
[ac_have_largefile=no],
["-D_FILE_OFFSET_BITS=64"],
[AC_DEFINE([_FILE_OFFSET_BITS], [64],
[Number of bits in a file offset, on hosts where this is settable.])],
["-D_LARGE_FILES=1"],
[AC_DEFINE([_LARGE_FILES], [1],
[Define to 1 on platforms where this makes off_t a 64-bit type.])],
[AC_MSG_ERROR(
[internal error: bad value for \$ac_cv_sys_largefile_opts])])
AS_IF([test "$enable_year2038" != no],
[_AC_SYS_YEAR2038_PROBE])
AC_CONFIG_COMMANDS_PRE([_AC_SYS_YEAR2038_ENABLE])])
# AC_SYS_LARGEFILE
# ----------------
# By default, many hosts won't let programs access large files;
# one must use special compiler options to get large-file access to work.
# For more details about this brain damage please see:
# http://www.unix.org/version2/whatsnew/lfs20mar.html
# Additionally, on Linux file systems with 64-bit inodes a file that happens
# to have a 64-bit inode number cannot be accessed by 32-bit applications on
# Linux x86/x86_64. This can occur with file systems such as XFS and NFS.
AC_DEFUN([AC_SYS_LARGEFILE],
[AC_ARG_ENABLE([largefile],
[AS_HELP_STRING([--disable-largefile],
[omit support for large files])])dnl
AS_IF([test "$enable_largefile,$enable_year2038" != no,no],
[_AC_SYS_LARGEFILE_PROBE])])
])# m4_ifndef AC_SYS_YEAR2038_RECOMMENDED
# Enable large files on systems where this is implemented by Gnulib, not by the
# system headers.
# Set the variables WINDOWS_64_BIT_OFF_T, WINDOWS_64_BIT_ST_SIZE if Gnulib
# overrides ensure that off_t or 'struct size.st_size' are 64-bit, respectively.
AC_DEFUN([gl_LARGEFILE],
[
AC_REQUIRE([AC_CANONICAL_HOST])
case "$host_os" in
mingw* | windows*)
dnl Native Windows.
dnl mingw64 defines off_t to a 64-bit type already, if
dnl _FILE_OFFSET_BITS=64, which is ensured by AC_SYS_LARGEFILE.
AC_CACHE_CHECK([for 64-bit off_t], [gl_cv_type_off_t_64],
[AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM(
[[#include <sys/types.h>
int verify_off_t_size[sizeof (off_t) >= 8 ? 1 : -1];
]],
[[]])],
[gl_cv_type_off_t_64=yes], [gl_cv_type_off_t_64=no])
])
if test $gl_cv_type_off_t_64 = no; then
WINDOWS_64_BIT_OFF_T=1
else
WINDOWS_64_BIT_OFF_T=0
fi
dnl Some mingw versions define, if _FILE_OFFSET_BITS=64, 'struct stat'
dnl to 'struct _stat32i64' or 'struct _stat64' (depending on
dnl _USE_32BIT_TIME_T), which has a 32-bit st_size member.
AC_CACHE_CHECK([for 64-bit st_size], [gl_cv_member_st_size_64],
[AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM(
[[#include <sys/types.h>
struct stat buf;
int verify_st_size_size[sizeof (buf.st_size) >= 8 ? 1 : -1];
]],
[[]])],
[gl_cv_member_st_size_64=yes], [gl_cv_member_st_size_64=no])
])
if test $gl_cv_member_st_size_64 = no; then
WINDOWS_64_BIT_ST_SIZE=1
else
WINDOWS_64_BIT_ST_SIZE=0
fi
;;
*)
dnl Nothing to do on gnulib's side.
dnl A 64-bit off_t is
dnl - already the default on Mac OS X, FreeBSD, NetBSD, OpenBSD, IRIX,
dnl OSF/1, Cygwin,
dnl - enabled by _FILE_OFFSET_BITS=64 (ensured by AC_SYS_LARGEFILE) on
dnl glibc, HP-UX, Solaris,
dnl - enabled by _LARGE_FILES=1 (ensured by AC_SYS_LARGEFILE) on AIX,
dnl - impossible to achieve on Minix 3.1.8.
WINDOWS_64_BIT_OFF_T=0
WINDOWS_64_BIT_ST_SIZE=0
;;
esac
])
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