National Instruments 320682C TCP Library Function Reference

Chapter 7 TCP Library

program is invoked to process the request. The parameter prototypes for the TCP callback

functions in LabWindows/CVI are defined below:

int CallbackFunction (int handle, int xType, int errCode,

void *callbackData);

where

handle represents the conversation handle

xType represents the transaction type (see table below)

errCode for TCP_DISCONNECT, is negative if the connection is being terminated due to an

error

callbackData is a user-defined data value.

All of the TCP transaction types (xType) that can trigger a callback function are listed in

Table 7-2.

Table 7-2. TCP Transaction Types (xType)

xType Server Client When ?

TCP_CONNECT Y N When a new client requests for

connection.

TCP_DISCONNECT Y Y When conversation partner quits.

TCP_DATAREADY Y Y When conversation partner sends

data.

Refer to the descriptions for RegisterTCPServer and ConnectToTCPServer for more

information about the TCP callback function.

TCP Library Function Reference

int status = ClientTCPRead (unsigned int conversationHandle, void *dataBuffer,

unsigned int dataSize, unsigned int timeout);

Purpose

Reads data from a TCP server application when it contains data that is ready for TCP network

transmission.