1Tcl_AppInit(3) Tcl Library Procedures Tcl_AppInit(3)
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8 Tcl_AppInit - perform application-specific initialization
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11 #include <tcl.h>
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13 int
14 Tcl_AppInit(interp)
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17 Tcl_Interp *interp (in) Interpreter for the application.
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22 Tcl_AppInit is a “hook” procedure that is invoked by the main programs
23 for Tcl applications such as tclsh and wish. Its purpose is to allow
24 new Tcl applications to be created without modifying the main programs
25 provided as part of Tcl and Tk. To create a new application you write
26 a new version of Tcl_AppInit to replace the default version provided by
27 Tcl, then link your new Tcl_AppInit with the Tcl library.
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29 Tcl_AppInit is invoked by Tcl_Main and Tk_Main after their own initial‐
30 ization and before entering the main loop to process commands. Here
31 are some examples of things that Tcl_AppInit might do:
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33 [1] Call initialization procedures for various packages used by the
34 application. Each initialization procedure adds new commands to
35 interp for its package and performs other package-specific ini‐
36 tialization.
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38 [2] Process command-line arguments, which can be accessed from the
39 Tcl variables argv and argv0 in interp.
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41 [3] Invoke a startup script to initialize the application.
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43 [4] Use the routines Tcl_SetStartupScript and Tcl_GetStartupScript
44 to set or query the file and encoding that the active Tcl_Main
45 or Tk_Main routine will use as a startup script.
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47 Tcl_AppInit returns TCL_OK or TCL_ERROR. If it returns TCL_ERROR then
48 it must leave an error message in for the interpreter's result; other‐
49 wise the result is ignored.
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51 In addition to Tcl_AppInit, your application should also contain a pro‐
52 cedure main that calls Tcl_Main as follows:
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54 Tcl_Main(argc, argv, Tcl_AppInit);
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56 The third argument to Tcl_Main gives the address of the application-
57 specific initialization procedure to invoke. This means that you do
58 not have to use the name Tcl_AppInit for the procedure, but in practice
59 the name is nearly always Tcl_AppInit (in versions before Tcl 7.4 the
60 name Tcl_AppInit was implicit; there was no way to specify the proce‐
61 dure explicitly). The best way to get started is to make a copy of the
62 file tclAppInit.c from the Tcl library or source directory. It already
63 contains a main procedure and a template for Tcl_AppInit that you can
64 modify for your application.
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68 Tcl_Main(3)
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72 application, argument, command, initialization, interpreter
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76Tcl 7.0 Tcl_AppInit(3)