From 171199159214f2f548132a98988435f9a450d3ef Mon Sep 17 00:00:00 2001 From: Zack Weinberg Date: Wed, 1 Mar 2017 08:17:07 -0500 Subject: Remove _IO_MTSAFE_IO from public headers. _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. --- ChangeLog | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'ChangeLog') diff --git a/ChangeLog b/ChangeLog index 8d2cfed606..b08ac488ff 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,17 @@ +2017-05-11 Zack Weinberg + + * 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. + 2016-05-10 Adhemerval Zanella * sysdeps/powerpc/powerpc32/backtrace.c (is_sigtramp_address): Use -- cgit 1.4.1