Tcl_AppInit(3)

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NAME
       Tcl_AppInit - perform application-specific initialization

SYNOPSIS
       #include <<tcl.h>>

       int
       Tcl_AppInit(interp)

ARGUMENTS
       Tcl_Interp   *interp   (in)      Interpreter    for    the
                                        application.
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DESCRIPTION
       Tcl_AppInit is a ``hook'' procedure that is invoked by the
       main programs for Tcl applications such as tclsh and wish.
       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 Tcl_AppInit to replace the default version pro-
       vided by Tcl, then link your new Tcl_AppInit with the  Tcl
       library.

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

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

       [2]    Process  command-line  arguments,  which   can   be
              accessed  from  the Tcl variables argv and argv0 in
              interp.

       [3]    Invoke a startup script to initialize the  applica-
              tion.

       Tcl_AppInit  returns  TCL_OK  or TCL_ERROR.  If it returns
       TCL_ERROR  then  it  must  leave  an  error   message   in
       interp-&gt;result;  otherwise the result is ignored.

       In  addition  to Tcl_AppInit, your application should also
       contain a procedure main that calls Tcl_Main as follows:
              Tcl_Main(argc, argv, Tcl_AppInit);
       The third argument to Tcl_Main gives the  address  of  the
       application-specific  initialization  procedure to invoke.
       This means that you don't have to use the name Tcl_AppInit

       for  the  procedure,  but  in  practice the name is nearly
       always Tcl_AppInit (in versions before Tcl  7.4  the  name
       Tcl_AppInit 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 tclAppInit.c from the Tcl library
       or source directory.  It already contains a main procedure
       and  a  template  for  Tcl_AppInit that you can modify for
       your application.

KEYWORDS
       application,  argument,  command,  initialization,  inter-
       preter