TclAppInit(3) Tcl Library Procedures TclAppInit(3)

NAME
       TclAppInit - perform application-specific initialization

SYNOPSIS
       ##iinncclluuddee <>

       int
       TTccllAAppppIInniitt(interp)

AARRGGUUMMEENNTTSS
       TclInterp   *interp   (in)      Interpreter for the application.



DESCRIPTION
       TTccllAAppppIInniitt  is  a  ``hook'' procedure that is invoked by the main pro-
       grams for Tcl applications such as ttccllsshh and wwiisshh.  Its purpose  is  to
       allow  new  Tcl  applications  to be created without modifying the main
       programs provided as part of Tcl and Tk.  To create a  new  application
       you  write  a new version of TTccllAAppppIInniitt to replace the default version
       provided by Tcl, then link your new TTccllAAppppIInniitt with the Tcl library.

       TTccllAAppppIInniitt is invoked after by TTccllMMaaiinn and TTkkMMaaiinn  after  their  own
       initialization  and  before entering the main loop to process commands.
       Here are some examples of things that TTccllAAppppIInniitt might do:

       [1]    Call initialization procedures for various packages used by  the
              application.  Each initialization procedure adds new commands to
              interp for its package and performs other package-specific  ini-
              tialization.

       [2]    Process  command-line  arguments, which can be accessed from the
              Tcl variables aarrggvv and aarrggvv00 in interp.

       [3]    Invoke a startup script to initialize the application.

       TTccllAAppppIInniitt returns TCLOK or TCLERROR.  If it returns TCLERROR  then
       it must leave an error message in for the interpreter's result;  other-
       wise the result is ignored.

       In addition to TTccllAAppppIInniitt, your application should also contain a pro-
       cedure mmaaiinn that calls TTccllMMaaiinn as follows:
              TclMain(argc, argv, TclAppInit);
       The  third  argument  to TTccllMMaaiinn gives the address of the application-
       specific initialization procedure to invoke.  This means that you don't
       have to use the name TTccllAAppppIInniitt for the procedure, but in practice the
       name is nearly always TTccllAAppppIInniitt (in versions before Tcl 7.4 the  name
       TTccllAAppppIInniitt  was  implicit;   there was no way to specify the procedure
       explicitly).  The best way to get started is to make a copy of the file
       ttccllAAppppIInniitt..cc from the Tcl library or source directory.  It already con-
       tains a mmaaiinn procedure and a template for TTccllAAppppIInniitt that you can mod-
       ify for your application.


KKEEYYWWOORRDDSS
       application, argument, command, initialization, interpreter



Tcl                                   7.0                       TclAppInit(3)