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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_setcancel-
         type(PTHREAD_CANCEL_DEFERRED,  &oldtype);  ...   pthread_setcancel-
         type(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 4.16 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)