tis_setcancelstate

Sets the caller's cancelability state.

Syntax

tis_setcancelstate(
                   state,
                   oldstate );
 



Argument         Data Type               Access

state            integer                 read

oldstate         integer                 write

C Binding

#include 


int
tis_setcancelstate (
            int   state,
            int   *oldstate );

Arguments

state

State of general cancelability to set for the calling thread. Valid state values are as follows:

• PTHREAD_CANCEL_ENABLE

• PTHREAD_CANCEL_DISABLE

oldstate

Previous cancelability state.

Description

When cancelability state is set to PTHREAD_CANCEL_DISABLE, a cancel cannot be delivered to the thread, even if a cancelable routine is called or asynchronous cancelability type is enabled.

When a thread is created, the default general cancelability state is PTHREAD_CANCEL_ENABLE. When this routine is called prior to loading threads, the cancel state propagates to the initial thread in the executing program.

Possible Problems When Disabling Cancelability

The most important use of cancel calls is to ensure that indefinite wait operations are terminated. For example, a thread waiting on some network connection, which may take days to respond (or may never respond), should be made cancelable.

When cancelability is disabled, no routine is cancelable. As a result, the user is unable to cancel the operation. When disabling cancelability, be sure that no long waits can occur or that it is necessary for other reasons to defer cancels around that particular region of code.

Return Values

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 state is not PTHREAD_CANCEL_ENABLE or
              PTHREAD_CANCEL_DISABLE.

Associated Routines

   tis_testcancel