NAME

       pthread_cleanup_push_defer_np,  pthread_cleanup_pop_restore_np - push and pop thread cancelation clean-up
       handlers while saving cancelability type

LIBRARY

       POSIX threads library (libpthread, -lpthread)

SYNOPSIS

       #include <pthread.h>

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

   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
       cancelation clean-up handlers.  In addition, it also saves the thread's current cancelability  type,  and
       sets  the  cancelability type to "deferred" (see pthread_setcanceltype(3)); this ensures that cancelation
       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 cancelation 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);

STANDARDS

       GNU; hence the suffix "_np" (nonportable) in the names.

HISTORY

       glibc 2.0

SEE ALSO

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

Linux man-pages 6.9.1                              2024-05-02                   pthread_cleanup_push_defer_np(3)