pthread_cleanup_push()
QNX SDP8.0C Library ReferenceAPIDeveloper
Push a function onto a thread's cancellation-cleanup stack
Synopsis:
#include <pthread.h>
void pthread_cleanup_push( void (routine)(void*),
void* arg );
Arguments:
- routine
- The handler that you want to push onto the thread's stack.
- arg
- A pointer to whatever data you want to pass to the function when it's called.
Library:
libc
Use the -l c option to qcc to link against this library. This library is usually included automatically.
Description:
The pthread_cleanup_push() function pushes the given cancellation-cleanup handler routine onto the calling thread's cancellation-cleanup stack.
The cancellation-cleanup handler is popped from the stack and invoked with argument arg when the thread:
- exits (i.e., calls pthread_exit())
- acts on a cancellation request
- calls pthread_cleanup_pop() with a nonzero argument
Note:
The pthread_cleanup_push() macro expands to a few lines of code
that start with an opening brace (
{), but don't have a matching
closing brace (}).
You must pair pthread_cleanup_push() with
pthread_cleanup_pop() within the same lexical scope.
Examples:
Use a cancellation cleanup handler to free resources, such as a mutex, when a thread is terminated:
#include <pthread.h>
pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
void unlock( void * arg )
{
pthread_mutex_unlock( &lock );
}
void * function( void * arg )
{
while( 1 )
{
pthread_mutex_lock( &lock );
pthread_cleanup_push( &unlock, NULL );
/*
Any of the possible cancellation points could
go here.
*/
pthread_testcancel();
pthread_cleanup_pop( 1 );
}
}
Classification:
| Safety: | |
|---|---|
| Cancellation point | No |
| Signal handler | Yes |
| Thread | Yes |
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