diff options
Diffstat (limited to 'NEWS')
| -rw-r--r-- | NEWS | 57 |
1 files changed, 27 insertions, 30 deletions
@@ -27,36 +27,33 @@ GNU Autoconf NEWS - User visible changes. ** New features -*** New macros AC_SYS_YEAR2038 and AC_SYS_YEAR2038_REQUIRED. - These macros attempt to enlarge time_t to 64 bits, on systems where - it has historically been only 32 bits wide, and therefore (assuming - the usual Unix epoch) cannot represent dates after mid-January of - 2038 (hence the names). The difference between the two is that - AC_SYS_YEAR2038_REQUIRED unconditionally causes 'configure' to error - out if 64-bit time_t is not available. - - Enlarging time_t to 64 bits is likely to have the side effect of - enlarging off_t and related types to 64 bits as well, as if you - had used AC_SYS_LARGEFILE. See the manual for details. - - Library authors should be cautious about adding these macros to - their configure scripts; they can break binary backward compatibility. - -*** New macro AC_SYS_LARGEFILE_REQUIRED. - This macro is the same as the existing AC_SYS_LARGEFILE except that - it will cause 'configure' to error out if 64-bit off_t is not available, - and it does not provide a --disable-largefile option. - -*** AC_SYS_LARGEFILE now optionally arranges to enlarge time_t. - As an experimental measure to make it easier to rebuild old programs - with support for dates after Jan 2038, if you regenerate any configure - script that uses AC_SYS_LARGEFILE (but not AC_SYS_YEAR2038) using - Autoconf 2.72, it will gain an --enable-year2038 option. When the - program is configured with this option, time_t will be enlarged if - possible, as if AC_SYS_YEAR2038 had been used. - - Using this option in a library build also potentially breaks binary - backward compatibility. +*** New macro AC_SYS_YEAR2038. + This causes 'configure' to widen time_t if possible on systems where + time_t by default cannot represent file and other timestamps after + January 2038. Widening is possible only on 32-bit GNU/Linux x86 and + ARM systems with glibc 2.34 or later. To prevent widening, + configure with --disable-year2038. + + This macro also has the effects as AC_SYS_LARGEFILE, because in + practice time_t cannot be widened without large-file sypport. + + Application and library builders should take care that packages + configured with --enable-year2038 and --disable-year2038 options + are configured consistently, to avoid breaking binary compatibility. + This is similar to longstanding consistency requirements with + --enable-largefile and --disable-largefile. + +*** AC_SYS_LARGEFILE now optionally arranges to widen time_t. + It now acts like AC_SYS_YEAR2038, except 'configure' defaults to + --disable-year2038 unless AC_SYS_YEAR2038 is also present. + As with AC_SYS_YEAR2038, application and library builders should + configure consistently. + +*** New macros AC_SYS_LARGEFILE_REQUIRED and AC_SYS_YEAR2038_REQUIRED. + These act like AC_SYS_LARGEFILE and AC_SYS_YEAR2038 respectively, + except that they require large-file and year-2038 support respectively. + As with AC_SYS_YEAR2038, application and library builders should + configure consistently. *** AC_USE_SYSTEM_EXTENSIONS now enables C23 Annex F extensions by defining __STDC_WANT_IEC_60559_EXT__. |