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C++17 requires quick_exit(3) to be async-signal safe.

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Make it safe, and update man page with the useful information.

Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
This commit is contained in:
kib 2017-11-04 10:52:58 +00:00
parent 8113f89b71
commit 18687b45c8
2 changed files with 18 additions and 2 deletions
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13
lib/libc/stdlib/quick_exit.3
View File

@ -24,7 +24,7 @@
.\"
.\" $FreeBSD$
.\"
.Dd December 13, 2014
.Dd November 4, 2017
.Dt QUICK_EXIT 3
.Os
.Sh NAME
@ -44,6 +44,17 @@ with
.Xr at_quick_exit 3
but not any C++ destructors or cleanup code registered with
.Xr atexit 3 .
The
.Xr stdio 3
file buffers are not flushed.
.Pp
The function
.Fn quick_exit
is
.Em async-signal safe
when the functions registered with
.Xr at_quick_exit 3
are.
.Sh RETURN VALUES
The
.Fn quick_exit

7
lib/libc/stdlib/quick_exit.c
View File

@ -26,6 +26,8 @@
* $FreeBSD$
*/
#include <sys/types.h>
#include <machine/atomic.h>
#include <stdlib.h>
#include <pthread.h>
@ -60,6 +62,7 @@ at_quick_exit(void (*func)(void))
h->cleanup = func;
pthread_mutex_lock(&atexit_mutex);
h->next = handlers;
__compiler_membar();
handlers = h;
pthread_mutex_unlock(&atexit_mutex);
return (0);
@ -74,7 +77,9 @@ quick_exit(int status)
* XXX: The C++ spec requires us to call std::terminate if there is an
* exception here.
*/
for (h = handlers; NULL != h; h = h->next)
for (h = handlers; NULL != h; h = h->next) {
__compiler_membar();
h->cleanup();
}
_Exit(status);
}