| 1 | # year2038.m4 serial 7
|
|---|
| 2 | dnl Copyright (C) 2017-2021 Free Software Foundation, Inc.
|
|---|
| 3 | dnl This file is free software; the Free Software Foundation
|
|---|
| 4 | dnl gives unlimited permission to copy and/or distribute it,
|
|---|
| 5 | dnl with or without modifications, as long as this notice is preserved.
|
|---|
| 6 |
|
|---|
| 7 | dnl Attempt to ensure that 'time_t' can go past the year 2038 and that
|
|---|
| 8 | dnl the functions 'time', 'stat', etc. work with post-2038 timestamps.
|
|---|
| 9 |
|
|---|
| 10 | AC_DEFUN([gl_YEAR2038_EARLY],
|
|---|
| 11 | [
|
|---|
| 12 | AC_REQUIRE([AC_CANONICAL_HOST])
|
|---|
| 13 | case "$host_os" in
|
|---|
| 14 | mingw*)
|
|---|
| 15 | AC_DEFINE([__MINGW_USE_VC2005_COMPAT], [1],
|
|---|
| 16 | [For 64-bit time_t on 32-bit mingw.])
|
|---|
| 17 | ;;
|
|---|
| 18 | esac
|
|---|
| 19 | ])
|
|---|
| 20 |
|
|---|
| 21 | # gl_YEAR2038_TEST_INCLUDES
|
|---|
| 22 | # -------------------------
|
|---|
| 23 | AC_DEFUN([gl_YEAR2038_TEST_INCLUDES],
|
|---|
| 24 | [[
|
|---|
| 25 | #include <time.h>
|
|---|
| 26 | /* Check that time_t can represent 2**32 - 1 correctly. */
|
|---|
| 27 | #define LARGE_TIME_T \\
|
|---|
| 28 | ((time_t) (((time_t) 1 << 30) - 1 + 3 * ((time_t) 1 << 30)))
|
|---|
| 29 | int verify_time_t_range[(LARGE_TIME_T / 65537 == 65535
|
|---|
| 30 | && LARGE_TIME_T % 65537 == 0)
|
|---|
| 31 | ? 1 : -1];
|
|---|
| 32 | ]])
|
|---|
| 33 |
|
|---|
| 34 | # gl_YEAR2038_BODY(REQUIRE-YEAR2038-SAFE)
|
|---|
| 35 | -----------------------------------------
|
|---|
| 36 | AC_DEFUN([gl_YEAR2038_BODY],
|
|---|
| 37 | [
|
|---|
| 38 | AC_ARG_ENABLE([year2038],
|
|---|
| 39 | [ --disable-year2038 omit support for timestamps past the year 2038])
|
|---|
| 40 | AS_IF([test "$enable_year2038" != no],
|
|---|
| 41 | [
|
|---|
| 42 | dnl On many systems, time_t is already a 64-bit type.
|
|---|
| 43 | dnl On those systems where time_t is still 32-bit, it requires kernel
|
|---|
| 44 | dnl and libc support to make it 64-bit. For glibc 2.34 and later on Linux,
|
|---|
| 45 | dnl defining _TIME_BITS=64 and _FILE_OFFSET_BITS=64 is needed on x86 and ARM.
|
|---|
| 46 | dnl
|
|---|
| 47 | dnl On native Windows, the system include files define types __time32_t
|
|---|
| 48 | dnl and __time64_t. By default, time_t is an alias of
|
|---|
| 49 | dnl - __time32_t on 32-bit mingw,
|
|---|
| 50 | dnl - __time64_t on 64-bit mingw and on MSVC (since MSVC 8).
|
|---|
| 51 | dnl But when compiling with -D__MINGW_USE_VC2005_COMPAT, time_t is an
|
|---|
| 52 | dnl alias of __time64_t.
|
|---|
| 53 | dnl And when compiling with -D_USE_32BIT_TIME_T, time_t is an alias of
|
|---|
| 54 | dnl __time32_t.
|
|---|
| 55 | AC_CACHE_CHECK([for time_t past the year 2038], [gl_cv_type_time_t_y2038],
|
|---|
| 56 | [AC_COMPILE_IFELSE(
|
|---|
| 57 | [AC_LANG_SOURCE([gl_YEAR2038_TEST_INCLUDES])],
|
|---|
| 58 | [gl_cv_type_time_t_y2038=yes], [gl_cv_type_time_t_y2038=no])
|
|---|
| 59 | ])
|
|---|
| 60 | if test "$gl_cv_type_time_t_y2038" = no; then
|
|---|
| 61 | AC_CACHE_CHECK([for 64-bit time_t with _TIME_BITS=64],
|
|---|
| 62 | [gl_cv_type_time_t_bits_macro],
|
|---|
| 63 | [AC_COMPILE_IFELSE(
|
|---|
| 64 | [AC_LANG_SOURCE([[#define _TIME_BITS 64
|
|---|
| 65 | #define _FILE_OFFSET_BITS 64
|
|---|
| 66 | ]gl_YEAR2038_TEST_INCLUDES])],
|
|---|
| 67 | [gl_cv_type_time_t_bits_macro=yes],
|
|---|
| 68 | [gl_cv_type_time_t_bits_macro=no])
|
|---|
| 69 | ])
|
|---|
| 70 | if test "$gl_cv_type_time_t_bits_macro" = yes; then
|
|---|
| 71 | AC_DEFINE([_TIME_BITS], [64],
|
|---|
| 72 | [Number of bits in a timestamp, on hosts where this is settable.])
|
|---|
| 73 | dnl AC_SYS_LARGFILE also defines this; it's OK if we do too.
|
|---|
| 74 | AC_DEFINE([_FILE_OFFSET_BITS], [64],
|
|---|
| 75 | [Number of bits in a file offset, on hosts where this is settable.])
|
|---|
| 76 | gl_cv_type_time_t_y2038=yes
|
|---|
| 77 | fi
|
|---|
| 78 | fi
|
|---|
| 79 | if test $gl_cv_type_time_t_y2038 = no; then
|
|---|
| 80 | AC_COMPILE_IFELSE(
|
|---|
| 81 | [AC_LANG_SOURCE(
|
|---|
| 82 | [[#ifdef _USE_32BIT_TIME_T
|
|---|
| 83 | int ok;
|
|---|
| 84 | #else
|
|---|
| 85 | error fail
|
|---|
| 86 | #endif
|
|---|
| 87 | ]])],
|
|---|
| 88 | [AC_MSG_FAILURE(
|
|---|
| 89 | [The 'time_t' type stops working after January 2038.
|
|---|
| 90 | Remove _USE_32BIT_TIME_T from the compiler flags.])],
|
|---|
| 91 | [# If not cross-compiling and $1 says we should check,
|
|---|
| 92 | # and 'touch' works with a large timestamp, then evidently wider time_t
|
|---|
| 93 | # is desired and supported, so fail and ask the builder to fix the
|
|---|
| 94 | # problem. Otherwise, just warn the builder.
|
|---|
| 95 | m4_ifval([$1],
|
|---|
| 96 | [if test $cross_compiling = no \
|
|---|
| 97 | && TZ=UTC0 touch -t 210602070628.15 conftest.time 2>/dev/null; then
|
|---|
| 98 | case `TZ=UTC0 LC_ALL=C ls -l conftest.time 2>/dev/null` in
|
|---|
| 99 | *'Feb 7 2106'* | *'Feb 7 17:10'*)
|
|---|
| 100 | AC_MSG_FAILURE(
|
|---|
| 101 | [The 'time_t' type stops working after January 2038,
|
|---|
| 102 | and your system appears to support a wider 'time_t'.
|
|---|
| 103 | Try configuring with 'CC="${CC} -m64"'.
|
|---|
| 104 | To build with a 32-bit time_t anyway (not recommended),
|
|---|
| 105 | configure with '--disable-year2038'.]);;
|
|---|
| 106 | esac
|
|---|
| 107 | rm -f conftest.time
|
|---|
| 108 | fi])
|
|---|
| 109 | if test "$gl_warned_about_y2038" != yes; then
|
|---|
| 110 | AC_MSG_WARN(
|
|---|
| 111 | [The 'time_t' type stops working after January 2038,
|
|---|
| 112 | and this package needs a wider 'time_t' type
|
|---|
| 113 | if there is any way to access timestamps after that.
|
|---|
| 114 | Configure with 'CC="${CC} -m64"' perhaps?])
|
|---|
| 115 | gl_warned_about_y2038=yes
|
|---|
| 116 | fi
|
|---|
| 117 | ])
|
|---|
| 118 | fi])
|
|---|
| 119 | ])
|
|---|
| 120 |
|
|---|
| 121 | AC_DEFUN([gl_YEAR2038],
|
|---|
| 122 | [
|
|---|
| 123 | gl_YEAR2038_BODY([require-year2038-safe])
|
|---|
| 124 | ])
|
|---|
