Wait for events that identify the async_work_group_copy operations to complete.
void wait_group_events(int num_events, event_t *event_list);
Wait for events that identify the async_work_group_copy(3clc) operations to complete. The event objects specified in event_list will be released after the wait is performed.
This function must be encountered by all work-items in a work-group executing the kernel with the same num_events and event objects specified in event_list; otherwise the results are undefined.
The kernel must wait for the completion of all async copies using the wait_group_events built-in function before exiting; otherwise the behavior is undefined.
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asyncCopyFunctions(3clc)
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OpenCL Specification
page 276, section 6.12.10 - Async Copies from Global to Local Memory...