Use pthread_testcancel(3THR) to establish a cancellation point for a thread.
Prototype: void pthread_testcancel(void);
#include <pthread.h> pthread_testcancel();
The pthread_testcancel() function is effective when thread cancellation is enabled and in deferred mode. Calling this function while cancellation is disabled has no effect.
Be careful to insert pthread_testcancel() only in sequences where it is safe to cancel a thread. In addition to programmatically establishing cancellation points through the pthread_testcancel() call, the pthreads standard specifies several cancellation points. See "Cancellation Points" for more details.
There is no return value.