newlib-cygwin/newlib/libc/stdlib/on_exit_args.c

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/*
* Static instance of _on_exit_args struct.
*
* When _REENT_SMALL is used, _atexit struct only contains a pointer to
* _on_exit_args struct, so this was always allocated with malloc() - even for
* the first 32 calls of atexit()-like functions, which are guaranteed to
* succeed, but could fail because of "out of memory" error. This is even worse
* when _ATEXIT_DYNAMIC_ALLOC is _NOT_ defined, in which case malloc() is not
* used by internals of atexit()-like functions. In such configuration all calls
* to the functions that need _on_exit_args struct (on_exit() and
* __cxa_atexit()) would fail.
*
* Thats why a static instance of _on_exit_args struct is provided for
* _REENT_SMALL configuration. This way the first 32 calls to atexit()-like
* functions don't need malloc() and will always succeed.
*
* Because this struct is not needed for "normal" atexit(), it is used as a weak
* reference in __register_exitproc(), but any use of on_exit() or
* __cxa_atexit() will force it to be linked.
*/
#include <reent.h>
#ifdef _REENT_SMALL
static struct _on_exit_args _on_exit_args_instance = {{_NULL}, {_NULL}, 0, 0};
struct _on_exit_args * const __on_exit_args = &_on_exit_args_instance;
#endif /* def _REENT_SMALL */