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ActiveTcl User Guide |
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Tcl_AppInit - perform application-specific initialization
#include <tcl.h>
int
Tcl_AppInit(interp)
- Tcl_Interp *interp
(in)
- Interpreter for the application.
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 provided by Tcl, then link your new Tcl_AppInit with
the Tcl library.
Tcl_AppInit is invoked 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 procedure 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 application.
Tcl_AppInit returns TCL_OK or TCL_ERROR. If
it returns TCL_ERROR then it must leave an error message in
for the interpreter's 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 do not 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.
application, argument, command, initialization, interpreter
Copyright © 1995-1997 Roger E. Critchlow Jr.
Copyright © 1993 The Regents of the University of California.
Copyright © 1994-1996 Sun Microsystems, Inc.