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glibc/sysdeps/unix/sysv/linux/features-time64.h
Adhemerval Zanella a4ed0471d7 Always define __USE_TIME_BITS64 when 64 bit time_t is used
It was raised on libc-help [1] that some Linux kernel interfaces expect
the libc to define __USE_TIME_BITS64 to indicate the time_t size for the
kABI.  Different than defined by the initial y2038 design document [2],
the __USE_TIME_BITS64 is only defined for ABIs that support more than
one time_t size (by defining the _TIME_BITS for each module).

The 64 bit time_t redirects are now enabled using a different internal
define (__USE_TIME64_REDIRECTS). There is no expected change in semantic
or code generation.

Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu, and
arm-linux-gnueabi

[1] https://sourceware.org/pipermail/libc-help/2024-January/006557.html
[2] https://sourceware.org/glibc/wiki/Y2038ProofnessDesign

Reviewed-by: DJ Delorie <dj@redhat.com>
2024-04-02 15:28:36 -03:00

43 lines
1.5 KiB
C

/* Features part to handle 64-bit time_t support.
Copyright (C) 2021-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
/* We need to know the word size in order to check the time size. */
#include <bits/wordsize.h>
#include <bits/timesize.h>
#if defined _TIME_BITS
# if _TIME_BITS == 64
# if ! defined (_FILE_OFFSET_BITS) || _FILE_OFFSET_BITS != 64
# error "_TIME_BITS=64 is allowed only with _FILE_OFFSET_BITS=64"
# endif
# define __USE_TIME_BITS64 1
# elif _TIME_BITS == 32
# if __TIMESIZE > 32
# error "_TIME_BITS=32 is not compatible with __TIMESIZE > 32"
# endif
# else
# error Invalid _TIME_BITS value (can only be 32 or 64-bit)
# endif
#elif __TIMESIZE == 64
# define __USE_TIME_BITS64 1
#endif
#if defined __USE_TIME_BITS64 && __TIMESIZE == 32
# define __USE_TIME64_REDIRECTS 1
#endif