newlib-cygwin/newlib/libc/errno/errno.c

/* The errno variable is stored in the reentrancy structure.  This
   function returns its address for use by the macro errno defined in
   errno.h.  */

#include <errno.h>
#include <reent.h>

#ifdef _REENT_THREAD_LOCAL
_Thread_local int _tls_errno;
#else /* !_REENT_THREAD_LOCAL */

#ifndef _REENT_ONLY

int *
__errno ()
{
  return &_REENT_ERRNO(_REENT);
}

#endif

#endif /* _REENT_THREAD_LOCAL */
import newlib-2000-02-17 snapshot 2000-02-18 03:39:52 +08:00			`/* The errno variable is stored in the reentrancy structure. This`
			`function returns its address for use by the macro errno defined in`
			`errno.h. */`

			`#include <errno.h>`
			`#include <reent.h>`

Add --enable-newlib-reent-thread-local option By default, Newlib uses a huge object of type struct _reent to store thread-specific data. This object is returned by __getreent() if the __DYNAMIC_REENT__ Newlib configuration option is defined. The reentrancy structure contains for example errno and the standard input, output, and error file streams. This means that if an application only uses errno it has a dependency on the file stream support even if it does not use it. This is an issue for lower end targets and applications which need to qualify the software according to safety standards (for example ECSS-E-ST-40C, ECSS-Q-ST-80C, IEC 61508, ISO 26262, DO-178, DO-330, DO-333). If the new _REENT_THREAD_LOCAL configuration option is enabled, then struct _reent is replaced by dedicated thread-local objects for each struct _reent member. The thread-local objects are defined in translation units which use the corresponding object. 2022-05-16 17:51:54 +08:00			`#ifdef _REENT_THREAD_LOCAL`
			`_Thread_local int _tls_errno;`
			`#else /* !_REENT_THREAD_LOCAL */`

import newlib-2000-02-17 snapshot 2000-02-18 03:39:52 +08:00			`#ifndef _REENT_ONLY`

			`int *`
			`__errno ()`
			`{`
Add _REENT_ERRNO(ptr) Add a _REENT_ERRNO() macro to encapsulate the access to the _errno member of struct reent. This will help to replace the structure member with a thread-local storage object in a follow up patch. Replace uses of __errno_r() with _REENT_ERRNO(). Keep __errno_r() macro for potential users outside of Newlib. 2022-01-18 17:13:04 +08:00			`return &_REENT_ERRNO(_REENT);`
import newlib-2000-02-17 snapshot 2000-02-18 03:39:52 +08:00			`}`

			`#endif`
Add --enable-newlib-reent-thread-local option By default, Newlib uses a huge object of type struct _reent to store thread-specific data. This object is returned by __getreent() if the __DYNAMIC_REENT__ Newlib configuration option is defined. The reentrancy structure contains for example errno and the standard input, output, and error file streams. This means that if an application only uses errno it has a dependency on the file stream support even if it does not use it. This is an issue for lower end targets and applications which need to qualify the software according to safety standards (for example ECSS-E-ST-40C, ECSS-Q-ST-80C, IEC 61508, ISO 26262, DO-178, DO-330, DO-333). If the new _REENT_THREAD_LOCAL configuration option is enabled, then struct _reent is replaced by dedicated thread-local objects for each struct _reent member. The thread-local objects are defined in translation units which use the corresponding object. 2022-05-16 17:51:54 +08:00
			`#endif /* _REENT_THREAD_LOCAL */`