This change is taken from Gnulib, and is needed for apps like GDB.
* lib/autoconf/specific.m4 (_AC_SYS_YEAR2038_TEST_INCLUDES)
(_AC_SYS_YEAR2038, AC_SYS_YEAR2038): New macros, taken (with
renaming) from Gnulib.
(_AC_SYS_LARGEFILE_MACRO_VALUE): #undef before #define.
(AC_SYS_LARGEFILE): Prefer AS_IF and AS_CASE to doing it by hand.
Widen time_t if possible, too. Define __MINGW_USE_VC2005_COMPAT
early if needed.
---
NEWS | 6 ++
doc/autoconf.texi | 33 +++++++++-
lib/autoconf/specific.m4 | 134 +++++++++++++++++++++++++++++++++++----
3 files changed, 159 insertions(+), 14 deletions(-)
diff --git a/NEWS b/NEWS
index ef0f5f83..204f95f1 100644
--- a/NEWS
+++ b/NEWS
@@ -21,7 +21,13 @@ GNU Autoconf NEWS - User visible changes.
that you will get a confusing error message if you run autoconf on
a configure.ac that neglects to use AC_INIT or AC_OUTPUT.
+*** AC_SYS_LARGEFILE now arranges for 64-bit time_t if possible.
+
+
** New features
+
+*** New macro AC_YEAR2038 for 64-bit time_t.
+
** Obsolete features and new warnings
*** Autoconf now quotes 'like this' instead of `like this'.
diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index fa5a9f48..209840c2 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -8869,6 +8869,7 @@ if the system supports @samp{#!}, @samp{no} if not.
@acindex{SYS_LARGEFILE}
@cvindex _FILE_OFFSET_BITS
@cvindex _LARGE_FILES
+@cvindex _TIME_BITS
@ovindex CC
@cindex Large file support
@cindex LFS
@@ -8877,13 +8878,15 @@ Arrange for 64-bit file offsets, known as
large-file support}. On some hosts, one must use special compiler
options to build programs that can access large files. Append any such
options to the output variable @code{CC}. Define
-@code{_FILE_OFFSET_BITS} and @code{_LARGE_FILES} if necessary.
+@code{_FILE_OFFSET_BITS}, @code{_LARGE_FILES}, and @code{_TIME_BITS}
+if necessary.
Large-file support can be disabled by configuring with the
@option{--disable-largefile} option.
-If you use this macro, check that your program works even when
-@code{off_t} is wider than @code{long int}, since this is common when
+If you use this macro, check that your program works even when the types
+@code{blkcnt_t}, @code{dev_t}, @code{ino_t}, @code{off_t}, and @code{time_t}
+are wider than @code{long int}, since this is common when
large-file support is enabled. For example, it is not correct to print
an arbitrary @code{off_t} value @code{X} with @code{printf ("%ld",
(long int) X)}. Also, when using this macro in concert with
@@ -8915,6 +8918,30 @@ system. If so, set the shell variable
@code{ac_cv_sys_posix_termios} to
@samp{yes}. If not, set the variable to @samp{no}.
@end defmac
+@defmac AC_SYS_YEAR2038
+@acindex{SYS_YEAR2038}
+@cvindex _TIME_BITS
+@ovindex CC
+@cindex Year 2038
+If the default @code{time_t} type is a signed 32-bit integer that stops
+working in the year 2038, then arrange to use a wider @code{time_t} if
+possible and report a fatal error otherwise. Define @code{_TIME_BITS}
+if necessary.
+
+Wider-time support can be disabled by configuring with the
+@option{--disable-year2038} option.
+
+Regardless of whether you use this macro, portable programs should not
+assume that @code{time_t} fits into @code{long int}. For example, it is
+not correct to print an arbitrary @code{time_t} value @code{X} with
+@code{printf ("%ld", (long int) X)}. Also, when using this macro in
+concert with @code{AC_CONFIG_HEADERS}, be sure that @file{config.h} is
+included before any system header.
+
+Although @code{AC_SYS_LARGFILE} also widens @code{time_t} if possible,
+it merely warns if this cannot be done, rather than reporting a fatal error.
+@end defmac
+
@node C and Posix Variants
@section C and Posix Variants
diff --git a/lib/autoconf/specific.m4 b/lib/autoconf/specific.m4
index 757d678b..0af41176 100644
--- a/lib/autoconf/specific.m4
+++ b/lib/autoconf/specific.m4
@@ -85,6 +85,112 @@ AU_DEFUN([AC_ARG_ARRAY], [],
with arguments. Remove this warning when you adjust your code.])
+# _AC_SYS_YEAR2038_TEST_INCLUDES
+# ------------------------------
+AC_DEFUN([_AC_SYS_YEAR2038_TEST_INCLUDES],
+[[
+ #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(REQUIRE-YEAR2038-SAFE)
+# ---------------------------------------
+AC_DEFUN([_AC_SYS_YEAR2038],
+[
+ AC_ARG_ENABLE([year2038],
+ [ --disable-year2038 omit support for timestamps past the year 2038])
+ AS_IF([test "$enable_year2038" != no],
+ [
+ dnl On many systems, time_t is already a 64-bit type.
+ dnl On those systems where time_t is still 32-bit, it requires kernel
+ dnl and libc support to make it 64-bit. For glibc 2.34 and later on Linux,
+ dnl defining _TIME_BITS=64 and _FILE_OFFSET_BITS=64 is needed on x86 and ARM.
+ dnl
+ dnl On native Windows, the system include files define types __time32_t
+ dnl and __time64_t. By default, time_t is an alias of
+ dnl - __time32_t on 32-bit mingw,
+ dnl - __time64_t on 64-bit mingw and on MSVC (since MSVC 8).
+ dnl But when compiling with -D__MINGW_USE_VC2005_COMPAT, time_t is an
+ dnl alias of __time64_t.
+ dnl And when compiling with -D_USE_32BIT_TIME_T, time_t is an alias of
+ dnl __time32_t.
+ AC_CACHE_CHECK([for time_t past the year 2038], [ac_cv_type_time_t_y2038],
+ [AC_COMPILE_IFELSE(
+ [AC_LANG_SOURCE([_AC_SYS_YEAR2038_TEST_INCLUDES])],
+ [ac_cv_type_time_t_y2038=yes], [ac_cv_type_time_t_y2038=no])
+ ])
+ if test "$ac_cv_type_time_t_y2038" = no; then
+ AC_CACHE_CHECK([for 64-bit time_t with _TIME_BITS=64],
+ [ac_cv_type_time_t_bits_macro],
+ [AC_COMPILE_IFELSE(
+ [AC_LANG_SOURCE([[#define _TIME_BITS 64
+ #define _FILE_OFFSET_BITS 64
+ ]_AC_SYS_YEAR2038_TEST_INCLUDES])],
+ [ac_cv_type_time_t_bits_macro=yes],
+ [ac_cv_type_time_t_bits_macro=no])
+ ])
+ if test "$ac_cv_type_time_t_bits_macro" = yes; then
+ AC_DEFINE([_TIME_BITS], [64],
+ [Number of bits in a timestamp, on hosts where this is settable.])
+ dnl AC_SYS_LARGFILE also defines this; it's OK if we do too.
+ AC_DEFINE([_FILE_OFFSET_BITS], [64],
+ [Number of bits in a file offset, on hosts where this is settable.])
+ ac_cv_type_time_t_y2038=yes
+ fi
+ fi
+ if test $ac_cv_type_time_t_y2038 = no; then
+ AC_COMPILE_IFELSE(
+ [AC_LANG_SOURCE(
+ [[#ifdef _USE_32BIT_TIME_T
+ int ok;
+ #else
+ error fail
+ #endif
+ ]])],
+ [AC_MSG_FAILURE(
+ [The 'time_t' type stops working after January 2038.
+ Remove _USE_32BIT_TIME_T from the compiler flags.])],
+ [# If not cross-compiling and $1 says we should check,
+ # and 'touch' works with a large timestamp, then evidently wider time_t
+ # is desired and supported, so fail and ask the builder to fix the
+ # problem. Otherwise, just warn the builder.
+ m4_ifval([$1],
+ [if test $cross_compiling = no \
+ && TZ=UTC0 touch -t 210602070628.15 conftest.time 2>/dev/null;
then
+ case `TZ=UTC0 LC_ALL=C ls -l conftest.time 2>/dev/null` in
+ *'Feb 7 2106'* | *'Feb 7 17:10'*)
+ AC_MSG_FAILURE(
+ [The 'time_t' type stops working after January 2038,
+ and your system appears to support a wider 'time_t'.
+ Try configuring with 'CC="${CC} -m64"'.
+ To build with a 32-bit time_t anyway (not recommended),
+ configure with '--disable-year2038'.]);;
+ esac
+ rm -f conftest.time
+ fi])
+ if test "$ac_warned_about_y2038" != yes; then
+ AC_MSG_WARN(
+ [The 'time_t' type stops working after January 2038,
+ and this package needs a wider 'time_t' type
+ if there is any way to access timestamps after that.
+ Configure with 'CC="${CC} -m64"' perhaps?])
+ ac_warned_about_y2038=yes
+ fi
+ ])
+ fi])
+])
+
+AC_DEFUN([AC_SYS_YEAR2038],
+[
+ _$0([require-year2038-safe])
+])
+
+
# _AC_SYS_LARGEFILE_TEST_INCLUDES
# -------------------------------
m4_define([_AC_SYS_LARGEFILE_TEST_INCLUDES],
@@ -112,7 +218,8 @@ m4_define([_AC_SYS_LARGEFILE_MACRO_VALUE],
[AC_LANG_PROGRAM([$5], [$6])],
[$3=no; break])
m4_ifval([$6], [AC_LINK_IFELSE], [AC_COMPILE_IFELSE])(
- [AC_LANG_PROGRAM([@%:@define $1 $2
+ [AC_LANG_PROGRAM([#undef $1
+#define $1 $2
$5], [$6])],
[$3=$2; break])
$3=unknown
@@ -138,9 +245,8 @@ rm -rf conftest*[]dnl
AC_DEFUN([AC_SYS_LARGEFILE],
[AC_ARG_ENABLE(largefile,
[ --disable-largefile omit support for large files])
-if test "$enable_largefile" != no; then
-
- AC_CACHE_CHECK([for special C compiler options needed for large files],
+AS_IF([test "$enable_largefile" != no],
+ [AC_CACHE_CHECK([for special C compiler options needed for large files],
ac_cv_sys_largefile_CC,
[ac_cv_sys_largefile_CC=no
if test "$GCC" != yes; then
@@ -165,13 +271,19 @@ if test "$enable_largefile" != no; then
ac_cv_sys_file_offset_bits,
[Number of bits in a file offset, on hosts where this is settable.],
[_AC_SYS_LARGEFILE_TEST_INCLUDES])
- if test $ac_cv_sys_file_offset_bits = unknown; then
- _AC_SYS_LARGEFILE_MACRO_VALUE(_LARGE_FILES, 1,
- ac_cv_sys_large_files,
- [Define for large files, on AIX-style hosts.],
- [_AC_SYS_LARGEFILE_TEST_INCLUDES])
- fi
-fi
+ AS_CASE([$ac_cv_sys_file_offset_bits],
+ [unknown],
+ [_AC_SYS_LARGEFILE_MACRO_VALUE([_LARGE_FILES], [1],
+ [ac_cv_sys_large_files],
+ [Define for large files, on AIX-style hosts.],
+ [_AC_SYS_LARGEFILE_TEST_INCLUDES])],
+ [64],
+ [_AC_SYS_YEAR2038()])])
+
+ AH_VERBATIM([__MINGW_USE_VC2005_COMPAT],
+[#if !defined __MINGW_USE_VC2005_COMPAT && defined __MINGW32__
+# define __MINGW_USE_VC2005_COMPAT 1 /* For 64-bit time_t. */
+#endif])
])# AC_SYS_LARGEFILE
--
2.37.1
