xfree86 man page for pthread_cleanup_push_defer_np

PTHREAD_CLEANUP_PUSH_DEFER_NP(3)			     Linux Programmer's Manual				  PTHREAD_CLEANUP_PUSH_DEFER_NP(3)

NAME
       pthread_cleanup_push_defer_np, pthread_cleanup_pop_restore_np - push and pop thread cancellation clean-up handlers while saving cancelabil-
       ity type

SYNOPSIS
       #include <pthread.h>

       void pthread_cleanup_push_defer_np(void (*routine)(void *),
					  void *arg);
       void pthread_cleanup_pop_restore_np(int execute);

       Compile and link with -pthread.

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       pthread_cleanup_push_defer_np(), pthread_cleanup_pop_defer_np():
	   _GNU_SOURCE

DESCRIPTION
       These functions are the same as pthread_cleanup_push(3) and pthread_cleanup_pop(3), except for the differences noted on this page.

       Like pthread_cleanup_push(3), pthread_cleanup_push_defer_np() pushes routine onto the thread's stack of cancellation clean-up handlers.	In
       addition,  it  also  saves  the	thread's current cancelability type, and sets the cancelability type to "deferred" (see pthread_setcancel-
       type(3)); this ensures that cancellation clean-up will occur even if the thread's cancelability type was "asynchronous" before the call.

       Like pthread_cleanup_pop(3), pthread_cleanup_pop_restore_np() pops the top-most clean-up handler from the thread's  stack  of  cancellation
       clean-up   handlers.    In   addition,	it  restores  the  thread's  cancelability  type  to  its  value  at  the  time  of  the  matching
       pthread_cleanup_push_defer_np().

       The caller must ensure that calls to these functions are paired within the same function, and at the same  lexical  nesting  level.   Other
       restrictions apply, as described in pthread_cleanup_push(3).

       This sequence of calls:

	   pthread_cleanup_push_defer_np(routine, arg);
	   pthread_cleanup_pop_restore_np(execute);

       is equivalent to (but shorter and more efficient than):

	   int oldtype;

	   pthread_cleanup_push(routine, arg);
	   pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &oldtype);
	   ...
	   pthread_setcanceltype(oldtype, NULL);
	   pthread_cleanup_pop(execute);

CONFORMING TO
       These functions are nonstandard GNU extensions; hence the suffix "_np" (nonportable) in the names.

SEE ALSO
       pthread_cancel(3), pthread_cleanup_push(3), pthread_setcancelstate(3), pthread_testcancel(3), pthreads(7)

COLOPHON
       This  page is part of release 4.15 of the Linux man-pages project.  A description of the project, information about reporting bugs, and the
       latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.

Linux								    2017-09-15					  PTHREAD_CLEANUP_PUSH_DEFER_NP(3)