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function  

tcp.reader

 
 

Library: TCP/IP client and server support (OMTCP)
Import: omtcp.xmd
Return type: String source

Returns: An external source containing the data read from the tcp connection.


Declaration

define external string source function tcp.reader
  of       value tcp.connection  Connection
  timeout  value integer         ms         optional
  protocol value tcp.io-protocol      Protocol   optional

Argument definitions

Connection
is an existing tcp.connection object.
ms
is the time to wait for a read operation to complete, expressed in milliseconds.
Protocol
specifies which I/O protocol is to be used.


Purpose

Use tcp.reader to obtain an external source object from which data will be read.

Requirements

Connection must exist (else external exception TCP05).

There may not be an active external source derived from Connection with tcp.reader (else external exception TCP04).

Usage Notes

If the received packet is corrupted, external exception TCP13 is thrown.

The timeout value applies primarily to data read from the returned external source. If a read operation times out, external exception TCP07 is thrown.

tcp.reader can be called more than once for a connection. All such derived sources read from the same source attachment, but such sources are subject to read-ahead, and it is generally the case that a read from a source will actually capture more data than is needed for immediate use. This means that if there are two or more sources derived from a connection, it is usually the case that data read from one such source is not that which immediately follows that read from another such source. As a consequence, only ONE external source can be derived from a connection at a time. That is, sources must be derived serially.

Example


  import "omtcp.xmd" prefixed by tcp.
  
  process
     local tcp.connection Connection-1
     local stream s
  
     set Connection-1 to tcp.connect to "localhost" on 5300
     tcp.set-buffering of Connection-1 enabled false
  
     open s with binary-mode as
        tcp.get-string from Connection-1
           protocol tcp.multi-packet
  
     put s "hello world"
     close s
  
     output tcp.reader of Connection-1
           protocol tcp.multi-packet

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OmniMark 9.1.0 Documentation Generated: September 2, 2010 at 1:38:10 pm
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