Requests delivery of a pending cancelation request to the calling
    thread.

1 - C Binding

    #include <pthread.h>

    void
    pthread_testcancel (void);

2 - Arguments

    None

3 - Description

    This routine requests delivery of a pending cancelation request
    to the calling thread. Thus, calling this routine creates a
    cancelation point within the calling thread.

    The cancelation request is delivered only if a request is pending
    for the calling thread and the calling thread's cancelability
    state is enabled. (A thread disables delivery of cancelation
    requests to itself by calling pthread_setcancelstate().)

    When called within very long loops, this routine ensures that
    a pending cancelation request is noticed by the calling thread
    within a reasonable amount of time.

4 - Return Values

    None

5 - Associated Routines

       pthread_setcancelstate()