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Chapter 3 Software Overview
NI-VXI User Manual 3-42 © National Instruments Corporation
SignalDeq (la, signalmask, signal)
SignalDeq
retrieves signals from the global signal queue. Two
methods are available to handle VXI signals. You can handle the
signals either by handlers or by queueing on a global signal queue. The
RouteSignal
function specifies which types of signals should be
handled by which of the two methods for each VXI logical address.
You can use
SignalDeq
to selectively dequeue a signal off of the
global signal queue. The signal specified by signalmask for the
specified logical address (la) is dequeued and returned in the output
parameter signal.
SignalEnq (signal)
SignalEnq
places signals at the end of the global signal queue. You
can use
SignalEnq
within a signal handler to queue a signal or to
simulate the reception of a signal by placing a value on the global
signal queue that was not actually received as a signal.
SignalJam (signal)
SignalJam
places signals at the front of the global signal queue.
SignalJam
can be used to simulate the reception of a signal by
placing a value on the global signal queue that was not actually
received as a signal. Because
SignalJam
places signal values on the
front of the global signal queue, the signal is guaranteed to be the first
of its type to be dequeued.
Note:
This function is intended only for debugging purposes.
WaitForSignal (la, signalmask, timeout, retsignal, retsignalmask)
WaitForSignal
waits for the specified maximum amount of time for
a particular signal (or class of signals) to be received.
Signalmask
defines the type(s) of signals that the application program waits for.
The timeout value specifies the maximum amount of time (in
milliseconds) to wait until the signal occurs. The signal that unblocks
the
WaitForSignal
call returns in the output parameter retsignal.
You should use the
WaitForSignal
function only when signals are
queued. A multitasking operating system lets you have any number of
WaitForSignal
calls pending. A non-multitasking operating system
permits only one pending
WaitForSignal
call.