pub struct ThreadPool(/* private fields */);Expand description
The GThreadPool struct represents a thread pool.
A thread pool is useful when you wish to asynchronously fork out the execution of work and continue working in your own thread. If that will happen often, the overhead of starting and destroying a thread each time might be too high. In such cases reusing already started threads seems like a good idea. And it indeed is, but implementing this can be tedious and error-prone.
Therefore GLib provides thread pools for your convenience. An added advantage is, that the threads can be shared between the different subsystems of your program, when they are using GLib.
To create a new thread pool, you use [new()][Self::new()].
It is destroyed by GLib::ThreadPool::free().
If you want to execute a certain task within a thread pool, use push().
To get the current number of running threads you call num_threads().
To get the number of still unprocessed tasks you call unprocessed().
To control the maximum number of threads for a thread pool, you use
max_threads(). and set_max_threads().
Finally you can control the number of unused threads, that are kept alive by GLib for future use.
The current number can be fetched with num_unused_threads().
The maximum number can be controlled by max_unused_threads() and
set_max_unused_threads(). All currently unused threads
can be stopped by calling stop_unused_threads().
Implementations§
Source§impl ThreadPool
impl ThreadPool
pub fn exclusive(max_threads: u32) -> Result<Self, Error>
Sourcepub fn push<T: Send + 'static, F: FnOnce() -> T + Send + 'static>(
&self,
func: F,
) -> Result<ThreadHandle<T>, Error>
pub fn push<T: Send + 'static, F: FnOnce() -> T + Send + 'static>( &self, func: F, ) -> Result<ThreadHandle<T>, Error>
Inserts @data into the list of tasks to be executed by @self.
When the number of currently running threads is lower than the maximal allowed number of threads, a new thread is started (or reused) with the properties given to g_thread_pool_new(). Otherwise, @data stays in the queue until a thread in this pool finishes its previous task and processes @data.
@error can be None to ignore errors, or non-None to report
errors. An error can only occur when a new thread couldn’t be
created. In that case @data is simply appended to the queue of
work to do.
Before version 2.32, this function did not return a success status.
§Returns
pub fn push_future<T: Send + 'static, F: FnOnce() -> T + Send + 'static>( &self, func: F, ) -> Result<impl Future<Output = Result<T>> + Send + Sync + 'static, Error>
Sourcepub fn set_max_threads(&self, max_threads: Option<u32>) -> Result<(), Error>
pub fn set_max_threads(&self, max_threads: Option<u32>) -> Result<(), Error>
Sets the maximal allowed number of threads for @self. A value of -1 means that the maximal number of threads is unlimited. If @self is an exclusive thread pool, setting the maximal number of threads to -1 is not allowed.
Setting @max_threads to 0 means stopping all work for @self. It is effectively frozen until @max_threads is set to a non-zero value again.
A thread is never terminated while calling @func, as supplied by g_thread_pool_new(). Instead the maximal number of threads only has effect for the allocation of new threads in g_thread_pool_push(). A new thread is allocated, whenever the number of currently running threads in @self is smaller than the maximal number.
@error can be None to ignore errors, or non-None to report
errors. An error can only occur when a new thread couldn’t be
created.
Before version 2.32, this function did not return a success status.
§max_threads
a new maximal number of threads for @self, or -1 for unlimited
§Returns
Sourcepub fn max_threads(&self) -> Option<u32>
pub fn max_threads(&self) -> Option<u32>
Sourcepub fn num_threads(&self) -> u32
pub fn num_threads(&self) -> u32
Returns the number of threads currently running in @self.
§Returns
the number of threads currently running
Sourcepub fn unprocessed(&self) -> u32
pub fn unprocessed(&self) -> u32
Sourcepub fn set_max_unused_threads(max_threads: Option<u32>)
pub fn set_max_unused_threads(max_threads: Option<u32>)
Sets the maximal number of unused threads to @max_threads. If @max_threads is -1, no limit is imposed on the number of unused threads.
The default value is 2.
§max_threads
maximal number of unused threads
Sourcepub fn max_unused_threads() -> Option<u32>
pub fn max_unused_threads() -> Option<u32>
Sourcepub fn num_unused_threads() -> u32
pub fn num_unused_threads() -> u32
Sourcepub fn stop_unused_threads()
pub fn stop_unused_threads()
Stops all currently unused threads. This does not change the maximal number of unused threads. This function can be used to regularly stop all unused threads e.g. from g_timeout_add().
Sourcepub fn set_max_idle_time(max_idle_time: u32)
pub fn set_max_idle_time(max_idle_time: u32)
This function will set the maximum @interval that a thread waiting in the pool for new tasks can be idle for before being stopped. This function is similar to calling g_thread_pool_stop_unused_threads() on a regular timeout, except this is done on a per thread basis.
By setting @interval to 0, idle threads will not be stopped.
The default value is 15000 (15 seconds).
§interval
the maximum @interval (in milliseconds) a thread can be idle
Sourcepub fn max_idle_time() -> u32
pub fn max_idle_time() -> u32
This function will return the maximum @interval that a thread will wait in the thread pool for new tasks before being stopped.
If this function returns 0, threads waiting in the thread pool for new work are not stopped.
§Returns
the maximum @interval (milliseconds) to wait for new tasks in the thread pool before stopping the thread