'\"
'\" Copyright (c) 1998-2000 Scriptics Corporation.
'\" All rights reserved.
'\"
.TH Tcl_Init 3 9.0 Tcl "Tcl Library Procedures"
.\" The -*- nroff -*- definitions below are for supplemental macros used
.\" in Tcl/Tk manual entries.
.\"
.\" .AP type name in/out ?indent?
.\"	Start paragraph describing an argument to a library procedure.
.\"	type is type of argument (int, etc.), in/out is either "in", "out",
.\"	or "in/out" to describe whether procedure reads or modifies arg,
.\"	and indent is equivalent to second arg of .IP (shouldn't ever be
.\"	needed;  use .AS below instead)
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.\"	name are examples of largest possible arguments that will be passed
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.\" .VS ?version? ?br?
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.\" .SO ?manpage?
.\"	Start of list of standard options for a Tk widget. The manpage
.\"	argument defines where to look up the standard options; if
.\"	omitted, defaults to "options". The options follow on successive
.\"	lines, in three columns separated by tabs.
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.\" .SE
.\"	End of list of standard options for a Tk widget.
.\"
.\" .OP cmdName dbName dbClass
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.\"	option's name as specified in the class command, dbName gives
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.\" .UL arg1 arg2
.\"	Print arg1 underlined, then print arg2 normally.
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.\" .QW arg1 ?arg2?
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.\" .PQ arg1 ?arg2?
.\"	Print an open parenthesis, arg1 in quotes, then arg2 normally
.\"	(for trailing punctuation) and then a closing parenthesis.
.\"
.\"	# Set up traps and other miscellaneous stuff for Tcl/Tk man pages.
.if t .wh -1.3i ^B
.nr ^l \n(.l
.ad b
.\"	# Start an argument description
.de AP
.ie !"\\$4"" .TP \\$4
.el \{\
.   ie !"\\$2"" .TP \\n()Cu
.   el          .TP 15
.\}
.ta \\n()Au \\n()Bu
.ie !"\\$3"" \{\
\&\\$1 \\fI\\$2\\fP (\\$3)
.\".b
.\}
.el \{\
.br
.ie !"\\$2"" \{\
\&\\$1	\\fI\\$2\\fP
.\}
.el \{\
\&\\fI\\$1\\fP
.\}
.\}
..
.\"	# define tabbing values for .AP
.de AS
.nr )A 10n
.if !"\\$1"" .nr )A \\w'\\$1'u+3n
.nr )B \\n()Au+15n
.\"
.if !"\\$2"" .nr )B \\w'\\$2'u+\\n()Au+3n
.nr )C \\n()Bu+\\w'(in/out)'u+2n
..
.AS Tcl_Interp Tcl_CreateInterp in/out
.\"	# BS - start boxed text
.\"	# ^y = starting y location
.\"	# ^b = 1
.de BS
.br
.mk ^y
.nr ^b 1u
.if n .nf
.if n .ti 0
.if n \l'\\n(.lu\(ul'
.if n .fi
..
.\"	# BE - end boxed text (draw box now)
.de BE
.nf
.ti 0
.mk ^t
.ie n \l'\\n(^lu\(ul'
.el \{\
.\"	Draw four-sided box normally, but don't draw top of
.\"	box if the box started on an earlier page.
.ie !\\n(^b-1 \{\
\h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul'
.\}
.el \}\
\h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul'
.\}
.\}
.fi
.br
.nr ^b 0
..
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.\"	# ^Y = starting y location
.\"	# ^v = 1 (for troff;  for nroff this doesn't matter)
.de VS
.if !"\\$2"" .br
.mk ^Y
.ie n 'mc \s12\(br\s0
.el .nr ^v 1u
..
.\"	# VE - end of vertical sidebar
.de VE
.ie n 'mc
.el \{\
.ev 2
.nf
.ti 0
.mk ^t
\h'|\\n(^lu+3n'\L'|\\n(^Yu-1v\(bv'\v'\\n(^tu+1v-\\n(^Yu'\h'-|\\n(^lu+3n'
.sp -1
.fi
.ev
.\}
.nr ^v 0
..
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.\"	# box/sidebar if in box/sidebar mode, then invoked standard
.\"	# page bottom macro.
.de ^B
.ev 2
'ti 0
'nf
.mk ^t
.if \\n(^b \{\
.\"	Draw three-sided box if this is the box's first page,
.\"	draw two sides but no top otherwise.
.ie !\\n(^b-1 \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c
.el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c
.\}
.if \\n(^v \{\
.nr ^x \\n(^tu+1v-\\n(^Yu
\kx\h'-\\nxu'\h'|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'|0u'\c
.\}
.bp
'fi
.ev
.if \\n(^b \{\
.mk ^y
.nr ^b 2
.\}
.if \\n(^v \{\
.mk ^Y
.\}
..
.\"	# DS - begin display
.de DS
.RS
.nf
.sp
..
.\"	# DE - end display
.de DE
.fi
.RE
.sp
..
.\"	# SO - start of list of standard options
.de SO
'ie '\\$1'' .ds So \\fBoptions\\fR
'el .ds So \\fB\\$1\\fR
.SH "STANDARD OPTIONS"
.LP
.nf
.ta 5.5c 11c
.ft B
..
.\"	# SE - end of list of standard options
.de SE
.fi
.ft R
.LP
See the \\*(So manual entry for details on the standard options.
..
.\"	# OP - start of full description for a single option
.de OP
.LP
.nf
.ta 4c
Command-Line Name:	\\fB\\$1\\fR
Database Name:	\\fB\\$2\\fR
Database Class:	\\fB\\$3\\fR
.fi
.IP
..
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.de CS
.RS
.nf
.ta .25i .5i .75i 1i
..
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.de CE
.fi
.RE
..
.\"	# UL - underline word
.de UL
\\$1\l'|0\(ul'\\$2
..
.\"	# QW - apply quotation marks to word
.de QW
.ie '\\*(lq'"' ``\\$1''\\$2
.\"" fix emacs highlighting
.el \\*(lq\\$1\\*(rq\\$2
..
.\"	# PQ - apply parens and quotation marks to word
.de PQ
.ie '\\*(lq'"' (``\\$1''\\$2)\\$3
.\"" fix emacs highlighting
.el (\\*(lq\\$1\\*(rq\\$2)\\$3
..
.\"	# QR - quoted range
.de QR
.ie '\\*(lq'"' ``\\$1''\\-``\\$2''\\$3
.\"" fix emacs highlighting
.el \\*(lq\\$1\\*(rq\\-\\*(lq\\$2\\*(rq\\$3
..
.\"	# MT - "empty" string
.de MT
.QW ""
..
.BS
.SH NAME
Tcl_Init \- find and source initialization script
.SH SYNOPSIS
.nf
\fB#include <tcl.h>\fR
.sp
int
\fBTcl_Init\fR(\fIinterp\fR)
.sp
const char *
\fBTcl_SetPreInitScript\fR(\fIscriptPtr\fR)
.sp
.VS TIP755
typedef int \fBTcl_PostInitProc\fR(\fBTcl_Interp *\fIinterp\fR, \fBvoid *\fIclientData\fR)
.sp
int
\fBTcl_RegisterPostInitProc\fR(\fIpostInitProc\fR, \fIclientData\fR)
.sp
int
\fBTcl_UnregisterPostInitProc\fR(\fIpostInitProc\fR, \fIclientData\fR)
.sp
int
\fBTcl_ClearPostInitProcs\fR(void)
.VE TIP755
.fi
.SH ARGUMENTS
.AS Tcl_Interp *interp
.AP Tcl_Interp *interp in
Interpreter to initialize.
.AP "const char" *scriptPtr in
Address of the initialization script.
.AP Tcl_PostInitProc *postInitProc in
Function to call post initialization of interpreter.
.AP "void" *clientData in
Arbitrary one-word value to pass to \fBpostInitProc\fR.
.BE
.SH DESCRIPTION
.PP
\fBTcl_Init\fR is a helper procedure that finds and \fBsource\fRs the
\fBinit.tcl\fR script, which should exist somewhere on the Tcl library
path.
.PP
\fBTcl_Init\fR is typically called from \fBTcl_AppInit\fR procedures.
.PP
\fBTcl_SetPreInitScript\fR registers the pre-initialization script and
returns the former (now replaced) script pointer.
A value of \fINULL\fR may be passed to not register any script.
The pre-initialization script is executed by \fBTcl_Init\fR before accessing
the file system. The purpose is to typically prepare a custom file system
(like an embedded zip-file) to be activated before the search.
.VS TIP755
.PP
\fBTcl_RegisterPostInitProc\fR registers a callback that should be invoked by
\fBTcl_Init\fR at the end of initialization of subsequently created
interpreters except safe interpreters. The function returns a Tcl return code.
.PP
This callback function is passed the interpreter being initialized and the
opaque \fIclientData\fR value that was passed at the time of registration. It
should return a Tcl return code. Multiple callbacks are supported and will be
invoked in the order of their registration except that an error return from a
callback will skip the remaining registrations. The Tcl return code from the
last callback invoked is returned as the return value from \fBTcl_Init\fR.
.PP
\fBTcl_UnregisterPostInitProc\fR unregisters a previously registered callback.
Both \fIpostInitProc\fR and \fIclientData\fR must match the the corresponding
values that were passed to \fBTcl_RegisterPostInitProc\fR. The function returns
a standard Tcl return code. It is not an error if there is no matching prior
registration.
.PP
The \fBTcl_ClearPostInitProcs\fR function unregisters all currently registered
callbacks.
.PP
Callback functions registered through \fBTcl_RegisterPostInitProc\fR may load
static packages, add commands, or set up other facilities so they are available
in all interpreters. They cannot however execute any code that may result in new
interpreters and should not delete the passed interpreter.
.PP
The `Tcl_RegisterPostInitProc` and `Tcl_UnregisterPostInitProc` functions may be
invoked from within a registered callback. However, the change in registration
will not have effect for the interpreter that is being initialized.
.VE TIP755
.PP
When used in stub-enabled embedders, the stubs table must be first initialized
using one of \fBTcl_InitSubsystems\fR, \fBTcl_SetPanicProc\fR,
\fBTcl_FindExecutable\fR
or \fBTclZipfs_AppHook\fR before \fBTcl_SetPreInitScript\fR may be called.
.SH "SEE ALSO"
Tcl_AppInit, Tcl_Main
.SH KEYWORDS
application, initialization, interpreter