Sets the calling thread's cancelability type.

1  –  C Binding

    #include <pthread.h>

    int
    pthread_setcanceltype (
                int   type,
                int   *oldtype);

2  –  Arguments

 type

    The cancelability type to set for the calling thread. The
    following are valid values:

       PTHREAD_CANCEL_DEFERRED
       PTHREAD_CANCEL_ASYNCHRONOUS

 oldtype

    Returns the previous cancelability type.

3  –  Description

    This routine sets the cancelability type and returns the previous
    type in location oldtype.

    When a thread's cancelability state is set to PTHREAD_CANCEL_
    DISABLE, (see pthread_setcancelstate()), a cancelation request
    cannot be delivered to that thread, even if a cancelable routine
    is called or asynchronous cancelability type is enabled.

    When the cancelability state is set to PTHREAD_CANCEL_ENABLE,
    cancelability depends on the thread's cancelability type, as
    follows:

    o  If the thread's cancelability type is PTHREAD_CANCEL_DEFERRED,
       the thread can only receive a cancelation request at a
       cancelation point (including condition waits, thread joins,
       and calls to pthread_testcancel()).

    o  If the thread's cancelability type is PTHREAD_CANCEL_
       ASYNCHRONOUS, the thread can be canceled at any point in its
       execution.

    When a thread is created, the default cancelability type is
    PTHREAD_CANCEL_DEFERRED.

                                 CAUTION

       If the asynchronous cancelability type is set, do not call
       any routine unless it is explicitly documented as "safe for
       asynchronous cancelation." Note that none of the general
       run-time libraries and none of the POSIX Threads libraries
       are safe for asynchronous cancelation except for pthread_
       setcanceltype() and pthread_setcancelstate().

       Use asynchronous cancelability only when you have a compute-
       bound section of code that carries no state and makes no
       routine calls.

4  –  Return Values

    On successful completion, this routine returns the previous
    cancelability type in oldtype.

    If an error condition occurs, this routine returns an integer
    value indicating the type of error. Possible return values are as
    follows:

    Return      Description

    0           Successful completion.
    [EINVAL]    The specified type is not PTHREAD_CANCEL_DEFERRED or
                PTHREAD_CANCEL_AYNCHRONOUS.

5  –  Associated Routines

       pthread_cancel()
       pthread_setcancelstate()
       pthread_testcancel()