handle_wait_many - wait for signals on multiple handles
#include <magenta/syscalls.h>
mx_status_t mx_handle_wait_many(uint32_t count, const mx_handle_t* handles,
const mx_signals_t* signals,
mx_time_t timeout,
uint32_t* result_index,
mx_signals_state_t* signals_states);
handle_wait_many() is a blocking syscall which causes the caller to wait until at least one of the specified signals is pending on one of the specified handle handles or timeout elapses.
The caller must provide count handles in the handles array and count signal bitmasks in the signals array. For each entry in the handles array, the corresponding entry in signals indicates which signals the calling thread should be resumed for.
The timeout parameter is relative time (from now) in nanoseconds which takes two special values: 0 and MX_TIME_INFINITE. The former causes the wait to complete immediately and the latter signals that wait will never times out.
Upon return, if non-null, the signals_states array is filled with a pair of bitmaps for each of the count specified handles, indicating which signals are pending and which are satisfiable on that particular handle.
It is possible to have the call return with a signals_states array with values different than the values that caused the wait to complete if other threads are further modifing the objects behind the handles.
If non-null and the return value is NO_ERROR or ERR_CANCELLED, result_index set to first handle that satisfied the wait (or was closed, respectively).
handle_wait_many() returns NO_ERROR on success when the wait was satisfied by the signals input, ERR_BAD_STATE when one of the signals inputs became unsatisfiable, or ERR_TIMED_OUT if the wait completed because timeout nanoseconds have elapsed.
In the event of ERR_TIMED_OUT, signals_states may reflect state changes that occurred after the timeout but before the syscall returned.
ERR_INVALID_ARGS handle isn't a valid handle or result_index or or signals_states were invalid pointers.
ERR_ACCESS_DENIED One or more of the provided handles does not have MX_RIGHT_READ and may not be waited upon.
ERR_CANCELLED One or more of the provided handles was invalidated (e.g., closed) during the wait.
ERR_NO_MEMORY (Temporary) failure due to lack of memory.
Currently the smallest timeout is 1 millisecond. Intervals smaller than that are equivalent to 1ms.