NDS client API

Classes
struct	DAQDChannel
	Channel data-base entry. More...
struct	DAQDRecHdr
	DAQD header record. More...
class	DAQSocket
	The DAQD socket class. More...

Data Access API (C++)

Access channel data through the network data server

This API provides a client interface for the "classic" NDS server. It allows the user to get channel data over the network. The syntax implemented by this interface is:

Function	DAQSocket method	NDS command
Get data from specified time	RequestData	start net-writer <start> <duration> [{"channel" ...} | all];
Get file names	RequestNames	start name-writer all;
Get available channel list	Available	status channels [2];
Get fast online data	RequestOnlineData	start fast-writer [{"channel" ...} | all];
Get slow online data	RequestOnlineData	start net-writer [{"channel" ...} | all];
Get trend data	RequestTrendData	start trend [60] net-writer <start> <duration> [{"channel" ...} | all];
Stop a net-writer	StopWriter	kill net-writer nnnnnnnn;

A typical online NDS client would do the following:

    //---------  Construct a DAQD socket 
    DAQSocket nds;

    //---------  Open a socket to the specified server port.
    const char* servername = "nds-server:port";
    nds.open(servername);
    if (!nds.TestOpen()) fail("Open failed!");

    //---------  Specify the channel to be read.
    const char* chan = "channel name";
    if (!nds.AddChannel(chan)) fail("Add channel failed!");
    if (nds.RequestOnlineData()) fail("Data Request failed");

    //---------  Specify the channel to be read.
    float* Samples = new float[data_len];
    while (1) {
        int nData = nds.GetData((char*) Samples, data_len);
	if (nData <= 0) break;
        ...  Process data ...
    }
    

Author:

John Zweizig

Version:

0.1; Last modified March 5, 2008

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