mirror of
git://sourceware.org/git/newlib-cygwin.git
synced 2025-01-19 04:49:25 +08:00
b0cb9f85ca
The _REENT_GLOBAL_STDIO_STREAMS was introduced by commit
668a4c8722090fffd10869dbb15b879651c1370d in 2017. Since then it was enabled by
default for RTEMS. Recently, the option was enabled for Cygwin which
previously used an alternative implementation to use global stdio streams.
In Newlib, the stdio streams are defined to thread-specific pointers
_reent::_stdin, _reent::_stdout and _reent::_stderr. If the option is disabled
(the default for most systems), then these pointers are initialized to
thread-specific FILE objects which use file descriptors 0, 1, and 2,
respectively. There are at least three problems with this:
(1) The thread-specific FILE objects are closed by _reclaim_reent(). This
leads to problems with language run-time libraries that provide wrappers to
the C/POSIX stdio streams (for example C++ and Ada), since they use the
thread-specific FILE objects of the initialization thread. In case the
initialization thread is deleted, then they use freed memory.
(2) Since thread-specific FILE objects are used with a common output device via
file descriptors 0, 1 and 2, the locking at FILE object level cannot ensure
atomicity of the output, e.g. a call to printf().
(3) There are resource managment issues, see:
https://sourceware.org/pipermail/newlib/2022/019558.html
https://bugs.linaro.org/show_bug.cgi?id=5841
This patch enables the _REENT_GLOBAL_STDIO_STREAMS behaviour for all Newlib
configurations and removes the option. This removes a couple of #ifdef blocks.
17 lines
641 B
C
17 lines
641 B
C
#include <reent.h>
|
|
|
|
/* Redeclare these symbols locally as weak so that the file containing
|
|
their definitions (along with a lot of other stuff) isn't sucked in
|
|
unless they are actually used by other compilation units. This is
|
|
important to reduce image size for targets with very small amounts
|
|
of memory. */
|
|
#ifdef _REENT_SMALL
|
|
extern __FILE __sf[3] _ATTRIBUTE ((weak));
|
|
#endif
|
|
|
|
struct _reent __ATTRIBUTE_IMPURE_DATA__ _impure_data = _REENT_INIT (_impure_data);
|
|
#ifdef __CYGWIN__
|
|
extern struct _reent reent_data __attribute__ ((alias("_impure_data")));
|
|
#endif
|
|
struct _reent *__ATTRIBUTE_IMPURE_PTR__ _impure_ptr = &_impure_data;
|