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thread_pool_control()
Control the thread pool behavior

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thread_pool_control()

QNX SDP8.0C Library ReferenceAPIDeveloper

Control the thread pool behavior

Synopsis:

#include <sys/iofunc.h>
#include <sys/dispatch.h>

thread_pool_control( thread_pool_t * pool,
                     thread_pool_attr_t * attr,
                     uint16_t lower,
                     uint16_t upper,
                     unsigned flags )

Arguments:

pool

A thread pool handle that was returned by thread_pool_create().

attr

A pointer to a thread_pool_attr_t structure that specifies the attributes that you want to use for the thread pool. For more information, see Thread-pool attributes, in the documentation for thread_pool_create().

lower, upper

This function blocks until the number of threads created is strictly between the range of upper and lower, unless you set THREAD_POOL_CONTROL_NONBLOCK in flags.

flags

Which attributes you want to change for the thread pool; any combination of the following bits:

THREAD_POOL_CONTROL_HIWATER — adjust the high-water value of the number of threads allowed in the thread pool.
THREAD_POOL_CONTROL_INCREMENT — adjust the increment value of the number of threads.
THREAD_POOL_CONTROL_LOWATER — adjust the low-water value of the number of threads allowed in the thread pool.
THREAD_POOL_CONTROL_MAXIMUM — adjust the maximum value of the number of threads allowed in the thread pool.
THREAD_POOL_CONTROL_NONBLOCK — don't block while creating threads.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

Use thread_pool_control() to specify a thread pool's behavior and adjust its attributes.

Returns:

EOK: Success.
-1: An error occurred (errno is set).

Errors:

EAGAIN: A thread for this pool couldn't be created or the context for a thread couldn't be allocated.
EINVAL: The requested lower number of threads to create (lower) is greater than the requested upper number (upper).

Classification:


Safety:
Cancellation point	Yes
Signal handler	No
Thread	Yes

Page updated: August 11, 2025