Used to send a signal to a socket, the result of which is that any task
blocked on a read from the socket will leave the Blocked state (abort the
blocking operation), with the task's read operation
If the socket is part of a socket set (SocketSet_t), the call to
using that socket set, will also get interrupted and
FreeRTOS_SignalSocketFromISR() is a version of FreeRTOS_SignalSocket()
that can be used from an interrupt service routine (ISR).
*pxHigherPriorityTaskWoken must be initialised to 0.
FreeRTOS_SignalSocketFromISR() will set
*pxHigherPriorityTaskWoken to pdTRUE if sending the
signal to the socket caused a task to unblock, and
the unblocked task has a priority higher than the
currently running task.
If FreeRTOS_SignalSocket() sets this value to pdTRUE
then a context switch should be requested before the
interrupt is exited. The name of the macro used to
request a context switch from an ISR is dependent on the port,
and will be called either portYIELD_FROM_ISR() or
portEND_SWITCHING_ISR(). Refer to the documentation and examples provided for
the port in use.
If xSocket is not a valid socket then -pdFREERTOS_ERRNO_EINVAL is
returned. Otherwise 0 is returned.