mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-27 07:20:11 +00:00
1711991592
_IO_MTSAFE_IO controls whether stdio is *built* with support for
multithreading. In the distant past it might also have worked as a
feature selection macro, allowing library *users* to select
thread-safe or lock-free stdio at application build time, I haven't
done the archaeology. Nowadays, defining _IO_MTSAFE_IO while using
the installed headers, or in _ISOMAC mode, will cause libio.h to throw
syntax errors.
This patch removes _IO_MTSAFE_IO from the public headers
(specifically, from libio/libio.h). The most important thing it
controlled in there was whether libio.h defines _IO_lock_t itself or
expects stdio-lock.h to have done it, and we do still need a
inter-header communication macro for that, because stdio-lock.h can
only define _IO_lock_t as a typedef. I've invented
_IO_lock_t_defined, which is defined by both versions of stdio-lock.h.
_IO_MTSAFE_IO also controlled the definitions of a handful of macros
that _might_ count as part of the public libio.h interface. They are
now unconditionally given their non-_IO_MTSAFE_IO definition in
libio/libio.h, and include/libio.h redefines them with the
_IO_MTSAFE_IO definition. This should minimize the odds of breaking
old software that actually uses those macros.
I suspect that this entire mechanism is vestigial, and that glibc
won't build anymore if you *don't* define _IO_MTSAFE_IO, but that's
another patchset. The bulk of libio.h is internal-use-only stuff that
no longer makes sense to expose (libstdc++ gave up on making a FILE
the same object as a C++ filebuf *decades* ago) but that, too, is
another patchset.
* libio/libio.h: Condition dummy definition of _IO_lock_t on
_IO_lock_t_defined, not _IO_MTSAFE_IO. Unconditionally use the
non-_IO_MTSAFE_IO definitions for _IO_peekc, _IO_flockfile,
_IO_funlockfile, and _IO_ftrylockfile. Only define
_IO_cleanup_region_start and _IO_cleanup_region_end if not
already defined.
* include/libio.h: If _IO_MTSAFE_IO is defined, redefine
_IO_peekc, _IO_flockfile, _IO_funlockfile, and _IO_ftrylockfile
appropriately.
* sysdeps/generic/stdio-lock.h, sysdeps/nptl/stdio-lock.h:
Define _IO_lock_t_defined after defining _IO_lock_t.
46 lines
1.2 KiB
C
46 lines
1.2 KiB
C
#if !defined _ISOMAC && defined _IO_MTSAFE_IO
|
|
# include <stdio-lock.h>
|
|
#endif
|
|
#include <libio/libio.h>
|
|
|
|
#ifndef _ISOMAC
|
|
#ifndef _LIBC_LIBIO_H
|
|
#define _LIBC_LIBIO_H
|
|
|
|
libc_hidden_proto (__overflow)
|
|
libc_hidden_proto (__underflow)
|
|
libc_hidden_proto (__uflow)
|
|
libc_hidden_proto (__woverflow)
|
|
libc_hidden_proto (__wunderflow)
|
|
libc_hidden_proto (__wuflow)
|
|
libc_hidden_proto (_IO_free_backup_area)
|
|
libc_hidden_proto (_IO_free_wbackup_area)
|
|
libc_hidden_proto (_IO_padn)
|
|
libc_hidden_proto (_IO_putc)
|
|
libc_hidden_proto (_IO_sgetn)
|
|
libc_hidden_proto (_IO_vfprintf)
|
|
libc_hidden_proto (_IO_vfscanf)
|
|
|
|
#ifdef _IO_MTSAFE_IO
|
|
# undef _IO_peekc
|
|
# undef _IO_flockfile
|
|
# undef _IO_funlockfile
|
|
# undef _IO_ftrylockfile
|
|
|
|
# define _IO_peekc(_fp) _IO_peekc_locked (_fp)
|
|
# if _IO_lock_inexpensive
|
|
# define _IO_flockfile(_fp) \
|
|
if (((_fp)->_flags & _IO_USER_LOCK) == 0) _IO_lock_lock (*(_fp)->_lock)
|
|
# define _IO_funlockfile(_fp) \
|
|
if (((_fp)->_flags & _IO_USER_LOCK) == 0) _IO_lock_unlock (*(_fp)->_lock)
|
|
# else
|
|
# define _IO_flockfile(_fp) \
|
|
if (((_fp)->_flags & _IO_USER_LOCK) == 0) _IO_flockfile (_fp)
|
|
# define _IO_funlockfile(_fp) \
|
|
if (((_fp)->_flags & _IO_USER_LOCK) == 0) _IO_funlockfile (_fp)
|
|
# endif
|
|
#endif /* _IO_MTSAFE_IO */
|
|
|
|
#endif
|
|
#endif
|