huschi.net

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 4.15 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)