ZBasic System Library
248
ZBasic Microcontrollers
Type
Subroutine
Invocation
PutQueue(queue, var, count)
Parameter
Method
Type
Description
queue
ByRef
array of Byte
The queue to which to write data.
var
ByRef
any type
The variable from which to read data to be written to
the queue.
count
ByVal
int16
The number of bytes to write to the queue.
Discussion
This routine reads data from the variable and writes it to the specified queue. If there is insufficient space
in the queue, the calling task will suspend until space becomes available. Note, particularly, that no data
will be written until there is room for all the data to be written. This has two important ramifications.
Firstly, if the number of bytes to be written is larger than the data capacity of the queue, the write will
never complete. Secondly, if data is never taken out of the queue thus making room for the additional
data, the write will also never complete.
Note that the number of bytes to write may be larger than the named variable. If this is the case, data will
be taken from subsequent memory locations until the write count is satisfied. This may or may not be
what you intended to occur.
Note, also, that before any queue operations are performed, the queue data structure must be initialized.
See the discussion of OpenQueue() for more details. Also, attempting to put data in a queue that has
been assigned to a Com port as the receive queue will produce undefined results.
Example
Dim outQueue(1 to 40) as Byte
Dim lval as Long
Call OpenQueue(outQueue, SizeOf(outQueue))
lval = &H55aa
Call PutQueue(outQueue, lval, SizeOf(lval))
Compatibility
BasicX allows any type for the first parameter. The ZBasic implementation requires that it be an array of
Byte.
See Also
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