TDynamicDataQueue.Top function
Gets the data for the first queue entry, but does not remove it from the queue.
Declaration
function Top(var Buffer; Count: Integer): Integer
function Top(AStream: TStream; Count: Integer): IntegerArguments
Buffer | Untyped buffer where the queue item is stored. |
Count | Number of bytes for the item data. |
AStream | TStream instance where the item data is stored. |
Function result
Number of bytes needed for item data in the queue.
Description
Top is an overloaded Integer function used to get the item data
stored at the top of the FIFO queue without removing it from the queue
internal storage. Overloaded variants are provided to get and store item data
as a sequence of arbitrary byte values, either in an untyped buffer or in a
TStream instance.
Please note: Top assumes that AStream is already positioned where
the item data will be written. It does not reposition the stream instance. Be
aware that writing to a stream can raise an exception.
Top calls the PopTopInternal method to perform the actions needed
to get the data for the queue item from the top of FIFO queue.
The return value contains the number of bytes needed for the item data in the internal storage for the queue.
Use Push to enqueue a new item to the bottom of the FIFO queue.
Use Pop to get and remove the item data at the top of the queue.
See also
An experiment, built from development snapshots. Not the official Free Pascal or Lazarus documentation.