mirror of
git://git.sv.gnu.org/autoconf
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Restore *_REQUIRED macros
As per: https://lists.gnu.org/r/autoconf-patches/2022-12/msg00004.html
This commit is contained in:
Paul Eggert
parent
f612e10a80
commit
845c3d2d7a
40
NEWS
40
NEWS
@ -27,18 +27,36 @@ GNU Autoconf NEWS - User visible changes.
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** New features
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*** AC_SYS_LARGEFILE now optionally arranges to widen time_t.
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It now causes 'configure' to gain an --enable-year2038 option which
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widens time_t if possible on systems where time_t by default cannot
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represent file timestamps and other timestamps after January 2038.
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As with off_t, ino_t, etc., if library ABIs depend on time_t width,
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applications should be configured consistently with libraries.
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*** New macros AC_SYS_YEAR2038 and AC_SYS_YEAR2038_REQUIRED.
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These macros attempt to enlarge time_t to 64 bits, on systems where
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it has historically been only 32 bits wide, and therefore (assuming
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the usual Unix epoch) cannot represent dates after mid-January of
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2038 (hence the names). The difference between the two is that
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AC_SYS_YEAR2038_REQUIRED unconditionally causes 'configure' to error
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out if 64-bit time_t is not available.
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*** New macro AC_SYS_YEAR2038.
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This acts like AC_SYS_LARGEFILE, except that it causes 'configure'
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to default to --enable-year2038. In a future Autoconf version,
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AC_SYS_LARGEFILE is planned to do this too, so the two macros will
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become equivalent.
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Enlarging time_t to 64 bits is likely to have the side effect of
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enlarging off_t and related types to 64 bits as well, as if you
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had used AC_SYS_LARGEFILE. See the manual for details.
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Library authors should be cautious about adding these macros to
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their configure scripts; they can break binary backward compatibility.
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*** New macro AC_SYS_LARGEFILE_REQUIRED.
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This macro is the same as the existing AC_SYS_LARGEFILE except that
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it will cause 'configure' to error out if 64-bit off_t is not available,
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and it does not provide a --disable-largefile option.
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*** AC_SYS_LARGEFILE now optionally arranges to enlarge time_t.
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As an experimental measure to make it easier to rebuild old programs
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with support for dates after Jan 2038, if you regenerate any configure
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script that uses AC_SYS_LARGEFILE (but not AC_SYS_YEAR2038) using
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Autoconf 2.72, it will gain an --enable-year2038 option. When the
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program is configured with this option, time_t will be enlarged if
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possible, as if AC_SYS_YEAR2038 had been used.
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Using this option in a library build also potentially breaks binary
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backward compatibility.
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*** AC_USE_SYSTEM_EXTENSIONS now enables C23 Annex F extensions
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by defining __STDC_WANT_IEC_60559_EXT__.
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@ -8798,95 +8798,72 @@ if the system supports @samp{#!}, @samp{no} if not.
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@defmac AC_SYS_LARGEFILE
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@acindex{SYS_LARGEFILE}
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@cvindex _FILE_OFFSET_BITS
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@cvindex _TIME_BITS
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@ovindex CC
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@cindex Large file support
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@cindex LFS
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If the default @code{off_t} type is a 32-bit integer so
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applications can deal only with files containing less than 2 GiB,
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make a wider @code{off_t} available if the system supports this.
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This may also widen several other types related to files and file
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systems, including @code{blkcnt_t}, @code{dev_t}, @code{ino_t},
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@code{fsblkcnt_t}, and @code{fsfilcnt_t}.
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If the default @code{off_t} type is a 32-bit integer, and therefore
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cannot be used to work with files larger than 4 gigabytes, arrange to
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make a larger @code{off_t} available, if the system supports this.
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Several other types related to the sizes of files and file systems will
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also be enlarged: @code{ino_t}, @code{blkcnt_t}, @code{fsblkcnt_t},
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@code{fsfilcnt_t}, and possibly @code{dev_t}.
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Also, arrange for a @command{configure} option to request widening the
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type @code{time_t} as needed to represent file timestamps and other
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timestamps after January 2038. If year-2038 support is requested but
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@command{configure} fails to find a way to enable a wide @code{time_t}
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and inspection of the system suggests that this feature is available
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somehow, @command{configure} will error out.
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If a large @code{off_t} is available (whether or not any arrangements
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were necessary), the shell variable @code{ac_have_largefile} will be set
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to @samp{yes}; if not, it will be set to @samp{no}.
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In this version of Autoconf, the year-2038 @command{configure} option
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currently defaults to @code{--disable-year2038}. If you want the
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default to be @code{--enable-year2038}, you can use
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@code{AC_SYS_YEAR2038} instead of @code{AC_SYS_LARGEFILE}. In other
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words, packages that use @code{AC_SYS_LARGEFILE} can be made ready for
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the year 2038 either by switching to @code{AC_SYS_YEAR2038}, or by
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configuring with @option{--enable-year2038}. A future version of
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Autoconf is planned to change the @code{AC_SYS_LARGEFILE} default to
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@code{--enable-year2038}; when that happens, @code{AC_SYS_LARGEFILE} and
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@code{AC_SYS_YEAR2038} will be equivalent. @xref{AC_SYS_YEAR2038}.
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Preprocessor macros will be defined if necessary to make a larger
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@code{off_t} available. (For example, on many systems the macro
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@code{_FILE_OFFSET_BITS} will be defined.) Some of these macros only
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work if they are defined before the first system header is included;
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therefore, when using this macro in concert with
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@code{AC_CONFIG_HEADERS}, make sure that @file{config.h} is included
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before any system headers.
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Set the shell variable @code{ac_have_largefile} to to @samp{yes} or
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@code{no} depending on whether a wide @code{off_t} is available,
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regardless of whether arrangements were necessary. Similarly, set the
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shell variable @code{ac_have_year2038} to @code{yes} or @code{no}
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depending on whether a wide-enough @code{time_t} is available. If your
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package requires large-file or year-2038 support, you can use code like this:
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@example
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AS_IF([test $ac_have_year2038 = no],
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[AC_MSG_FAILURE([year-2038 support missing])])
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@end example
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Define preprocessor macros if necessary to make types wider; For
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example, on many systems the macros @code{_FILE_OFFSET_BITS} and
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@code{_TIME_BITS} can be defined. Some of these macros work only if
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they are defined before the first system header is included; therefore,
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when using this macro in concert with @code{AC_CONFIG_HEADERS}, make
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sure that @file{config.h} is included before any system headers.
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On a few older systems, also change the output variable @code{CC} to add
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special compiler options that are needed to enable large @code{off_t}.
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On a few older systems, the output variable @code{CC} will also be
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changed to add special compiler options that are needed to enable large
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@code{off_t}.
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Large-file support can be disabled by configuring with the
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@option{--disable-largefile} option, and year-2038 support can
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be enabled and disabled via the @option{--enable-year2038} and
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@option{--disable-year2038} options. These options have no effect on
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systems where types are wide enough by default.
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Large-file support is required for year-2038 support: if you configure
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with @option{--disable-largefile} on a platform with 32-bit
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@code{time_t}, then year-2038 support is not available.
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Disabling large-file or year-2038 support can have surprising effects,
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such as causing functions like @code{readdir} and @code{stat} to fail
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even on small files because their inode numbers are unrepresentable, or
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causing functions like @code{stat} to fail because a file's timestamp is
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out of range.
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@option{--disable-largefile} option. Note that this has no effect on
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systems where @code{off_t} is 64 bits or larger by default. Disabling
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large-file support can have surprising effects, such as causing
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functions like @code{readdir} and @code{stat} to fail on small files
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(because their @emph{inode numbers} are unrepresentable).
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Regardless of whether you use this macro, portable programs should not
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assume that any of the types listed above fit into a @code{long int}.
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For example, it is not portable to print an arbitrary @code{off_t} or
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@code{time_t} value @code{X} with @code{printf ("%ld", (long int) X)}.
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For example, it is not correct to print an arbitrary @code{off_t} value
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@code{X} with @code{printf ("%ld", (long int) X)}.
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The standard C library functions @code{fseek} and @code{ftell} do not
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use @code{off_t}. If you need to use either of these functions, you
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should use @code{AC_FUNC_FSEEKO} as well as @code{AC_SYS_LARGEFILE}, and
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then use their Posix replacements @code{fseeko} and @code{ftello}.
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@xref{AC_FUNC_FSEEKO}.
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Note that the standard C library functions @code{fseek} and @code{ftell}
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do not use @code{off_t}. If you need to use either of these functions,
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you should use @code{AC_FUNC_FSEEKO} as well as @code{AC_SYS_LARGEFILE},
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and then use their Posix replacements @code{fseeko} and @code{ftello},
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which @emph{do} use @code{off_t}, when available. @xref{AC_FUNC_FSEEKO}.
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When using @code{AC_SYS_LARGEFILE} in different packages that are linked
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together and that have ABIs that depend on the width of @code{off_t},
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@code{time_t} or related types, the simplest thing is to configure all
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components the same way. For example, if an application uses
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@code{AC_SYS_LARGEFILE} and is configured with
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@option{--enable-year2038}, libraries it links to with an @code{off_t}-
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or @code{time_t}-dependent ABI should be configured equivalently.
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Alternatively, you can modify libraries to support both 32- and 64-bit
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ABIs though this is more work and typically few libraries other than the
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C library itself are modified in this way.
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As of Autoconf 2.72, @code{AC_SYS_LARGEFILE} also @emph{optionally}
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arranges to enlarge @code{time_t}. This is to make it easier to build
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programs that support timestamps after 2038; many configure scripts will
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not need to be modified, only regenerated with newer Autoconf. When
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@code{AC_SYS_LARGEFILE} is used, and @code{AC_SYS_YEAR2038} is
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@emph{not} used, @code{time_t} will normally be left at the system's
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default size, but you can request it be enlarged by configuring with the
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@option{--enable-year2038} option. (When @code{AC_SYS_YEAR2038} is also
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used, @code{time_t} is enlarged if possible. @xref{AC_SYS_YEAR2038}.)
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@end defmac
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@defmac AC_SYS_LARGEFILE_REQUIRED
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@acindex{SYS_LARGEFILE_REQUIRED}
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This macro has the same effect as @code{AC_SYS_LARGEFILE},
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but also declares that the program being configured
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@emph{requires} support for large files.
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If a large @code{off_t} is unavailable,
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@command{configure} will error out.
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The @option{--disable-largefile} option will not be available.
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@end defmac
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@anchor{AC_SYS_LONG_FILE_NAMES}
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@defmac AC_SYS_LONG_FILE_NAMES
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@acindex{SYS_LONG_FILE_NAMES}
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@ -8908,9 +8885,55 @@ system. If so, set the shell variable @code{ac_cv_sys_posix_termios} to
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@anchor{AC_SYS_YEAR2038}
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@defmac AC_SYS_YEAR2038
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@acindex{SYS_YEAR2038}
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@cvindex _TIME_BITS
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@cindex Year 2038
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This is like @code{AC_SYS_LARGEFILE} except it defaults to enabling
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instead of disabling year-2038 support. @xref{AC_SYS_LARGEFILE}.
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If the default @code{time_t} type is a signed 32-bit integer,
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and therefore (assuming the usual Unix epoch) cannot represent
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timestamps after mid-January of 2038, arrange to make a larger
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@code{time_t} available, if the system supports this.
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If a large @code{time_t} is available (whether or not any arrangements
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were necessary), the shell variable @code{ac_have_year2038} will be set
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to @samp{yes}; if not, it will be set to @samp{no}.
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Preprocessor macros will be defined if necessary to make a larger
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@code{time_t} available. (For example, on some systems the macro
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@code{_TIME_BITS} will be defined.) Some of these macros only work if
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they are defined before the first system header is included; therefore,
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when using this macro in concert with @code{AC_CONFIG_HEADERS}, make
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sure that @file{config.h} is included before any system headers.
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Support for timestamps after 2038 can be disabled by configuring with
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the @option{--disable-year2038} option. Note that this has no effect on
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systems where @code{time_t} is 64 bits or larger by default.
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If this option is @emph{not} given, and @command{configure} fails to
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find a way to enable a large @code{time_t}, but inspection of the
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system suggests that this feature is available @emph{somehow}, it will
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error out.
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Regardless of whether you use this macro, portable programs should not
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assume that @code{time_t} fits into @code{long int}. For example, it is
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not correct to print an arbitrary @code{time_t} value @code{X} with
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@code{printf ("%ld", (long int) X)}.
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@strong{Caution:} If you are developing a shared library, and
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@code{time_t} appears anywhere in your library's public interface, use
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of this macro may break binary compatibility with older executables.
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@end defmac
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@defmac AC_SYS_YEAR2038_REQUIRED
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@acindex{SYS_YEAR2038_REQUIRED}
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This macro has the same effect as @code{AC_SYS_YEAR2038},
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but also declares that the program being configured
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@emph{requires} support for timestamps after mid-January of 2038.
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If a large @code{time_t} is unavailable,
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@command{configure} will @emph{unconditionally} error out
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(unlike the behavior of @code{AC_SYS_YEAR2038}).
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The @option{--disable-year2038} option will not be available.
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@strong{Caution:} If you are developing a shared library, and
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@code{time_t} appears anywhere in your library's public interface, use
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of this macro may break binary compatibility with older executables.
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@end defmac
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@node C and Posix Variants
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@ -156,6 +156,8 @@ AS_CASE([$ac_cv_sys_year2038_opts],
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["support not detected"],
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[ac_have_year2038=no
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AS_CASE([$enable_year2038],
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[required],
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[AC_MSG_FAILURE([support for timestamps after Jan 2038 is required])],
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[yes],
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[# If we're not cross compiling and 'touch' works with a large
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# timestamp, then we can presume the system supports wider time_t
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@ -202,19 +204,22 @@ AS_CASE([$ac_cv_sys_year2038_opts],
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# --enable-year2038, or a --disable-year2038, or no option at all to
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# the configure script. Note that this is expanded very late and
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# therefore there cannot be any code in the AC_ARG_ENABLE. The
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# default value for enable_year2038 is emitted unconditionally
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# default value for 'enable_year2038' is emitted unconditionally
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# because the generated code always looks at this variable.
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m4_define([_AC_SYS_YEAR2038_ENABLE],
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[m4_divert_text([DEFAULTS],
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m4_provide_if([AC_SYS_YEAR2038_REQUIRED],
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[enable_year2038=required],
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m4_provide_if([AC_SYS_YEAR2038],
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[enable_year2038=yes],
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[enable_year2038=no]))]dnl
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[enable_year2038=no])))]dnl
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[m4_provide_if([AC_SYS_YEAR2038_REQUIRED], [],
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[AC_ARG_ENABLE([year2038],
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m4_provide_if([AC_SYS_YEAR2038],
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[AS_HELP_STRING([--disable-year2038],
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[do not support timestamps after 2038])],
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[omit support for dates after Jan 2038])],
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[AS_HELP_STRING([--enable-year2038],
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[support timestamps after 2038])]))])
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[include support for dates after Jan 2038])]))])])
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# _AC_SYS_YEAR2038_OPT_IN
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# -----------------------
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@ -236,12 +241,28 @@ AC_DEFUN([_AC_SYS_YEAR2038_OPT_IN],
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# On systems where time_t is not always 64 bits, this probe can be
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# skipped by passing the --disable-year2038 option to configure.
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AC_DEFUN([AC_SYS_YEAR2038],
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[AC_REQUIRE([AC_SYS_LARGEFILE])]dnl
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[m4_provide_if([AC_SYS_LARGEFILE_REQUIRED], [],
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[AC_REQUIRE([AC_SYS_LARGEFILE])])]dnl
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[m4_provide_if([_AC_SYS_YEAR2038_PROBE], [], [dnl
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AS_IF([test "$enable_year2038" != no], [_AC_SYS_YEAR2038_PROBE])
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AC_CONFIG_COMMANDS_PRE([_AC_SYS_YEAR2038_ENABLE])
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])])
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# AC_SYS_YEAR2038_REQUIRED
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# ------------------------
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# Same as AC_SYS_YEAR2038, but declares that this program *requires*
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# support for large time_t. If we cannot find any way to make time_t
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# capable of representing values larger than 2**31 - 1, configure will
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# error out. Furthermore, no --enable-year2038 nor --disable-year2038
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# option will be available.
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AC_DEFUN([AC_SYS_YEAR2038_REQUIRED],
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[m4_provide_if([AC_SYS_LARGEFILE_REQUIRED], [],
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[AC_REQUIRE([AC_SYS_LARGEFILE])])]dnl
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[m4_provide_if([_AC_SYS_YEAR2038_PROBE], [], [dnl
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_AC_SYS_YEAR2038_PROBE
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AC_CONFIG_COMMANDS_PRE([_AC_SYS_YEAR2038_ENABLE])
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])])
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# _AC_SYS_LARGEFILE_TEST_CODE
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# ---------------------------
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# C code used to probe for large file support.
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@ -302,7 +323,9 @@ ac_have_largefile=yes
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AS_CASE([$ac_cv_sys_largefile_opts],
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["none needed"], [],
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["support not detected"],
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[ac_have_largefile=no],
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[ac_have_largefile=no
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AS_IF([test $enable_largefile = required],
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[AC_MSG_FAILURE([support for large files is required])])],
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["-D_FILE_OFFSET_BITS=64"],
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[AC_DEFINE([_FILE_OFFSET_BITS], [64],
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@ -323,16 +346,21 @@ _AC_SYS_YEAR2038_OPT_IN
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# _AC_SYS_LARGEFILE_ENABLE
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# ------------------------
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# Subroutine of AC_SYS_LARGEFILE. Note that this
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# Subroutine of AC_SYS_LARGEFILE. If AC_SYS_LARGEFILE_REQUIRED was
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# not used at any point in this configure script, add a
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# --disable-largefile option to the configure script. Note that this
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# is expanded very late and therefore there cannot be any code in the
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# AC_ARG_ENABLE. The default value for enable_largefile is emitted
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# AC_ARG_ENABLE. The default value for 'enable_largefile' is emitted
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# unconditionally because the generated shell code always looks at
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# this variable.
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m4_define([_AC_SYS_LARGEFILE_ENABLE],
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[m4_divert_text([DEFAULTS],
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enable_largefile=yes)]dnl
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m4_provide_if([AC_SYS_LARGEFILE_REQUIRED],
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[enable_largefile=required],
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[enable_largefile=yes]))]dnl
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[m4_provide_if([AC_SYS_LARGEFILE_REQUIRED], [],
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[AC_ARG_ENABLE([largefile],
|
||||
[AS_HELP_STRING([--disable-largefile], [omit support for large files])])])
|
||||
[AS_HELP_STRING([--disable-largefile], [omit support for large files])])])])
|
||||
|
||||
# AC_SYS_LARGEFILE
|
||||
# ----------------
|
||||
@ -344,13 +372,28 @@ m4_define([_AC_SYS_LARGEFILE_ENABLE],
|
||||
# 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.
|
||||
# This macro allows configuration to continue if the system doesn't support
|
||||
# large files.
|
||||
# large files; see also AC_SYS_LARGEFILE_REQUIRED.
|
||||
AC_DEFUN([AC_SYS_LARGEFILE],
|
||||
[m4_provide_if([_AC_SYS_LARGEFILE_PROBE], [], [dnl
|
||||
AS_IF([test "$enable_largefile" != no], [_AC_SYS_LARGEFILE_PROBE])
|
||||
AC_CONFIG_COMMANDS_PRE([_AC_SYS_LARGEFILE_ENABLE])
|
||||
])])
|
||||
|
||||
# AC_SYS_LARGEFILE_REQUIRED
|
||||
# -------------------------
|
||||
# Same as AC_SYS_LARGEFILE, but declares that this program *requires*
|
||||
# support for large files. If we cannot find a combination of compiler
|
||||
# options and #defines that makes 'off_t' capable of representing 2**63 - 1,
|
||||
# 'configure' will error out. Furthermore, 'configure' will not offer a
|
||||
# --disable-largefile command line option.
|
||||
# If both AC_SYS_LARGEFILE and AC_SYS_LARGEFILE_REQUIRED are used in the
|
||||
# same configure script -- in either order -- AC_SYS_LARGEFILE_REQUIRED wins.
|
||||
AC_DEFUN([AC_SYS_LARGEFILE_REQUIRED],
|
||||
[m4_provide_if([_AC_SYS_LARGEFILE_PROBE], [], [dnl
|
||||
_AC_SYS_LARGEFILE_PROBE
|
||||
AC_CONFIG_COMMANDS_PRE([_AC_SYS_LARGEFILE_ENABLE])
|
||||
])])
|
||||
|
||||
# AC_SYS_LONG_FILE_NAMES
|
||||
# ----------------------
|
||||
# Security: use a temporary directory as the most portable way of
|
||||
|
||||
Loading…
Reference in New Issue
Block a user