Submits a single function to the dispatch queue and causes the function to be executed the specified number of times.


void dispatch_apply_f(size_t iterations, dispatch_queue_t queue, void *context, void (*work)(void *, size_t));



The number of iterations to perform.


The queue on which to submit the function. It is recommended that you specify DISPATCH_APPLY_AUTO for this parameter, as that causes the block to run on a queue whose quality-of-service class is most appropriate for the current execution context.


The application-defined context parameter to pass to the function.


The application-defined function to invoke on the target queue. This parameter cannot be NULL. The block has no return value and takes the following parameters:


The pointer you specified in the context parameter.


The current iteration index.


This function submits an application-defined function to a dispatch queue for multiple invocations and waits for all iterations of the function to complete before returning. If the target queue is a concurrent queue returned by dispatch_get_global_queue, the function can be invoked concurrently, and it must therefore be reentrant-safe. Using this function with a concurrent queue can be useful as an efficient parallel for loop.

The current index of iteration is passed to each invocation of the function.

See Also

Executing a Task in Parallel


Submits a single block to the dispatch queue and causes the block to be executed the specified number of times.

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