pthread_cleanup_pop_restore_np3

Usage

Library

POSIX threads library (libpthread, -lpthread)

Overview

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);