[TR] - This C function is used to create a new command useable from the Tcl script level. The definition is

Tcl_Command
'''Tcl_CreateObjCommand'''(''interp'', ''cmdName'', ''proc'', ''clientData'', ''deleteProc'')

so it returns a Tcl_Command (which is a token for the command) and takes 5 arguments:

   * ''interp'' -  the interpreter in which to create the new command
   * ''cmdName'' - the name of the new command (possibly in a specific namespace)
   * ''proc'' - the name of a C function to handle the command execution when called by a script
   * ''clientData'' - some data associated with the command, when a state needs to be taken care of (a file for example); this is typically used where a ''proc'' is used to create a whole family of commands, such as the instances of a kind of [Tk] widget.
   * ''deleteProc'' - a C function to call when the command is deleted from the interpreter (used for cleanup of the ''clientData'') which may be NULL if no cleanup is needed.

A full example of the usage can be found in: [Hello World as a C extension]. Here is an example from the [sqlite] extension used to create the 'sqlite' command:

 Tcl_CreateObjCommand(interp, "sqlite", (Tcl_ObjCmdProc*)DbMain, 0, 0);

An example using the clientData feature is here (also from sqlite):

 Tcl_CreateObjCommand(interp, zArg, DbObjCmd, (char*)p, DbDeleteCmd);

Here, the clientData are used to "bind" the created command to the database file for which is was created. In this example zArgs is a variable to hold the name of the created command. The command will be handled by the DbObjCmd C function and the clientData are "(char*)p" in this case holding the data for the opened sqlite database, so the otherwise generic DbObjCmd function can operate on the right database file.

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[Category Tcl Library]