started by Theo Verelst

To make use a pipe or as here a general socket to connect a user interface with a progam or to link programs together is a long used and tried solution since at least X windows. Not that that always worked perfectly, but its pretty ok.

Also web servers/browsers, ftp, etc are examples of existing progams making use of socket IPC. The principle is clear enough: one makes a stream connection, and sends messages across with commands and data.

In practice, this doesn't work out all too easy, usually. This page presents an example to do most work completely automatically to make a tcl program connect with a C program, and have the C program execute functions under control of the tcl program.

Also, an example is easil created, where Tk is used to have a stack of buttons for testing this.

Major issues when making a socket link and programming code around it are:

   * newlines
   * end of line
   * end of message
   * flow control
   * process issues
   * connection control
   * error correction/sensitivity

The approach taken for this test version consists of the following steps:

   1. define a list of message names, which are also used as corresponding C function names
   2. make the socket connection possible both on C and Tcl side
   3. generate automatically the C message handler and the frame of the C functions
   4. generate Tcl/Tk code to make a button for each message
   5. save and compile the generated C file
   6. link it with the socket code
   7. run the resulting C program
   8. connect the tcl program
   9. test the buttons to see if the corresponding C functions get called.


Motivations and subsequent work include:

   * real time sound synthesis/analysis C code I have can be runtime tcl/tk controlled
   * idem for 3D graphics
   * webserver extensions in c or tcl
   * BWise-ification of the various blocks here
   * distributed applications (protocol based)

[http://82.168.209.239/Wiki/cframecon.jpg]

[http://82.168.209.239/Wiki/cframebut.jpg]

[http://82.168.209.239/Wiki/cframett.jpg]

[http://82.168.209.239/Wiki/cframecon.jpg]