PTHREAD_CLEANUP_PUSH_DEFER_Linux Programmer's 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 4.10 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				  2014-05-28  PTHREAD_CLEANUP_PUSH_DEFER_NP(3)