pthread_atfork()
QNX SDP8.0C Library ReferenceAPIDeveloper
Register fork handlers
Synopsis:
#include <pthread.h>
int pthread_atfork( void (*prepare)(void),
void (*parent)(void),
void (*child)(void) );
Arguments:
- prepare
- NULL, or a pointer to the handler to call before the fork.
- parent
- NULL, or a pointer to the handler to call after the fork in the parent process.
- child
- NULL, or a pointer to the handler to call after the fork in the child process.
Library:
libc
Use the -l c option to qcc to link against this library. This library is usually included automatically.
Description:
The pthread_atfork() function registers fork handler functions to be called before and after a fork(), in the context of the thread that called fork(). You can set one or more of the arguments to NULL to indicate no handler.
You can register multiple prepare, parent, and child fork handlers, by making additional calls to pthread_atfork(). In this case, the parent and child handlers are called in the order they were registered, and the prepare handlers are called in the reverse order.
Note:
- In the child handler, you can call only functions that are async-signal-safe (i.e., functions that you can safely call from a signal handler).
- It's possible to call fork() from a multithreaded process, but it can be very difficult
to do so safely, so we recommend that you call it only from single-threaded processes.
For more information, see
Using fork() in a multithreaded process
in theProcesses and Threads
chapter of Getting Started with the QNX OS.
Returns:
- EOK
- Success.
- ENOMEM
- Insufficient memory to record fork handlers.
Classification:
| Safety: | |
|---|---|
| Cancellation point | No |
| Signal handler | Yes |
| Thread | Yes |
Page updated: