Sending Live Data to XGRAPH
(Driving XGRAPH Interactively)

1. In the global-area of your program:

   	#include "utilities/soc_lib.c"
   	int soc;
      

2. In the initialization section of your program, open the socket with:

   	soc = makeConnect( "localhost", socno );
   

   Where socno is an integer socket number, such as 13330 .
   (Suggestion: Use socket numbers from 1000 to 16383.)

3. Everywhere that you want to write data to XGRAPH, where you normally wrote to a graph-file with:
   . . . fprintf(plotfile,"%f %f\n",x,y);
   Replace with:

   	sprintf(message,"%f %f", x, y );
   	send_soc( soc, message );
   
   (You can also write to the file at the same time by adding:
   		fprintf(plotfile,"%s\n",message);
   )
   
   (Note that you can send any XGRAPH command through the socket
    that you would normally write to a plot-file, such as:
   	color=8
   	next_line
           annotation 3.0 5.6  Any text you want
    etc..
   )

4. Make sure your program closes the socket after it is done writing everything to XGRAPH, by:

   	close_soc( soc );

5. Compile your application by adding the link-libs:

   	-lsocket -lnsl 

   to the end of your compile command. For example:

   	cc test.c -lsocket -lnsl -o test.exe

   (On Linux, -lnsl is not needed.)

Usage:

1. Invoke XGRAPH, telling the x-and-y ranges and the socket number to use. Run it in background.
   For example:

   	xgraph -x_range 0 20  -y_range 1 10  -soc 13330 &
   	

2. Invoke your user-application that connects to the given socket. For example:

   	sim.exe
   	

Notes:

• You must tell xgraph the X-Y range of your data-values prior to graphing live data, because xgraph must set the axes-ranges before it sees the data, so that it can display the data as it arrives. The convenient method to set the axes ranges is the x_range, and y_range command-line options.

• You can make the graph window pan right at any time via the socket command:   PAN_RIGHT . That is, send this command through the socket to xgraph, as in:

       send_soc( soc, "PAN_RIGHT\n" );

  This has the same effect as clicking the Pan Right button interactively. It is convenient for causing the graph to scroll horizontally as data arrives.

• If a user-application dies before closing the socket, the socket will automatically close anyway. But it may take a few minutes before that socket number becomes available again.

• A given user-program can drive multiple XGRAPH displays. Make sure to use a distinct "socket" number and pointer for each graph. For example:

  		    int soc1, soc2;
  		    soc1 = makeConnect("localhost",13330);
  		    soc2 = makeConnect("localhost",13331);

  Then start separate graphs:

  	xgraph -x_range 0 2 -y_range 1 9 -soc 13330 &
  	xgraph -x_range 0 2 -y_range 1 9 -soc 13331 &
     

• Conversely, multiple applications can write to a common graph. For example, to the same graph, open multiple sockets:

  	xgraph -x_range 0 2 -y_range 1 9 -soc 13330 -soc 13331  & 

• There is a simple example-test program, called: - livetest.c
  You can download it (right-click) and try it. Compile it with:

     On Solaris:
  		cc livetest.c -lsocket -lnsl -o livetest

     On Linux:
  		cc livetest.c -o livetest

  Try it by:

  	xgraph -soc 13330 -x_range 0 10 -y_range 0 7 -pl &
          livetest

• You can get the soc_lib.c and soc_lib.tar from soclib.tar.