man/man3/Tcl_DeleteInterp.3 - toolchains/skids - Git at Google

 '\"
 '\" Copyright (c) 1989-1993 The Regents of the University of California.
 '\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
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 '\" RCS: @(#) $Id: CrtInterp.3,v 1.7 2002/06/26 11:50:52 msofer Exp $
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 '\" The definitions below are for supplemental macros used in Tcl/Tk
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 '\" .AP type name in/out ?indent?
 '\"	Start paragraph describing an argument to a library procedure.
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 '\"	or "in/out" to describe whether procedure reads or modifies arg,
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 '\"	name are examples of largest possible arguments that will be passed
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 '\"	End of list of standard options for a Tk widget.
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 '\" .OP cmdName dbName dbClass
 '\"	Start of description of a specific option.  cmdName gives the
 '\"	option's name as specified in the class command, dbName gives
 '\"	the option's name in the option database, and dbClass gives
 '\"	the option's class in the option database.
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 '\" .UL arg1 arg2
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 '\" RCS: @(#) $Id: man.macros,v 1.4 2000/08/25 06:18:32 ericm Exp $
 '\"
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 .if t .wh -1.3i ^B
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 .   ie !"\\$2"" .TP \\n()Cu
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 ..
 .AS Tcl_Interp Tcl_CreateInterp in/out
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 .\}
 .el \}\
 \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul'
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 See the \\fBoptions\\fR manual entry for details on the standard options.
 ..
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 .de OP
 .LP
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 Command-Line Name:	\\fB\\$1\\fR
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 Database Class:	\\fB\\$3\\fR
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 .TH Tcl_CreateInterp 3 7.5 Tcl "Tcl Library Procedures"
 .BS
 .SH NAME
 Tcl_CreateInterp, Tcl_DeleteInterp, Tcl_InterpDeleted \- create and delete Tcl command interpreters
 .SH SYNOPSIS
 .nf
 \fB#include <tcl.h>\fR
 .sp
 Tcl_Interp *
 \fBTcl_CreateInterp\fR()
 .sp
 \fBTcl_DeleteInterp\fR(\fIinterp\fR)
 .sp
 int
 \fBTcl_InterpDeleted\fR(\fIinterp\fR)
 .SH ARGUMENTS
 .AS Tcl_Interp *interp
 .AP Tcl_Interp *interp in
 Token for interpreter to be destroyed.
 .BE

 .SH DESCRIPTION
 .PP
 \fBTcl_CreateInterp\fR creates a new interpreter structure and returns
 a token for it.  The token is required in calls to most other Tcl
 procedures, such as \fBTcl_CreateCommand\fR, \fBTcl_Eval\fR, and
 \fBTcl_DeleteInterp\fR.
 Clients are only allowed to access a few of the fields of
 Tcl_Interp structures;  see the \fBTcl_Interp\fR
 and \fBTcl_CreateCommand\fR man pages for details.
 The new interpreter is initialized with the built-in Tcl commands
 and with the variables documented in tclvars(n).  To bind in
 additional commands, call \fBTcl_CreateCommand\fR.
 .PP
 \fBTcl_DeleteInterp\fR marks an interpreter as deleted; the interpreter
 will eventually be deleted when all calls to \fBTcl_Preserve\fR for it have
 been matched by calls to \fBTcl_Release\fR. At that time, all of the
 resources associated with it, including variables, procedures, and
 application-specific command bindings, will be deleted.  After
 \fBTcl_DeleteInterp\fR returns any attempt to use \fBTcl_Eval\fR on the
 interpreter will fail and return \fBTCL_ERROR\fR. After the call to
 \fBTcl_DeleteInterp\fR it is safe to examine the interpreter's result,
 query or set the values of variables, define, undefine or retrieve
 procedures, and examine the runtime evaluation stack. See below, in the
 section \fBINTERPRETERS AND MEMORY MANAGEMENT\fR for details.
 .PP
 \fBTcl_InterpDeleted\fR returns nonzero if \fBTcl_DeleteInterp\fR was
 called with \fIinterp\fR as its argument; this indicates that the
 interpreter will eventually be deleted, when the last call to
 \fBTcl_Preserve\fR for it is matched by a call to \fBTcl_Release\fR. If
 nonzero is returned, further calls to \fBTcl_Eval\fR in this interpreter
 will return \fBTCL_ERROR\fR.
 .PP
 \fBTcl_InterpDeleted\fR is useful in deletion callbacks to distinguish
 between when only the memory the callback is responsible for is being
 deleted and when the whole interpreter is being deleted. In the former case
 the callback may recreate the data being deleted, but this would lead to an
 infinite loop if the interpreter were being deleted.

 .SH "INTERPRETERS AND MEMORY MANAGEMENT"
 .PP
 \fBTcl_DeleteInterp\fR can be called at any time on an interpreter that may
 be used by nested evaluations and C code in various extensions. Tcl
 implements a simple mechanism that allows callers to use interpreters
 without worrying about the interpreter being deleted in a nested call, and
 without requiring special code to protect the interpreter, in most cases.
 This mechanism ensures that nested uses of an interpreter can safely
 continue using it even after \fBTcl_DeleteInterp\fR is called.
 .PP
 The mechanism relies on matching up calls to \fBTcl_Preserve\fR with calls
 to \fBTcl_Release\fR. If \fBTcl_DeleteInterp\fR has been called, only when
 the last call to \fBTcl_Preserve\fR is matched by a call to
 \fBTcl_Release\fR, will the interpreter be freed. See the manual entry for
 \fBTcl_Preserve\fR for a description of these functions.
 .PP
 The rules for when the user of an interpreter must call \fBTcl_Preserve\fR
 and \fBTcl_Release\fR are simple:
 .TP
 Interpreters Passed As Arguments
 Functions that are passed an interpreter as an argument can safely use the
 interpreter without any special protection. Thus, when you write an
 extension consisting of new Tcl commands, no special code is needed to
 protect interpreters received as arguments. This covers the majority of all
 uses.
 .TP
 Interpreter Creation And Deletion
 When a new interpreter is created and used in a call to \fBTcl_Eval\fR,
 \fBTcl_VarEval\fR, \fBTcl_GlobalEval\fR, \fBTcl_SetVar\fR, or
 \fBTcl_GetVar\fR, a pair of calls to \fBTcl_Preserve\fR and
 \fBTcl_Release\fR should be wrapped around all uses of the interpreter.
 Remember that it is unsafe to use the interpreter once \fBTcl_Release\fR
 has been called. To ensure that the interpreter is properly deleted when
 it is no longer needed, call \fBTcl_InterpDeleted\fR to test if some other
 code already called \fBTcl_DeleteInterp\fR; if not, call
 \fBTcl_DeleteInterp\fR before calling \fBTcl_Release\fR in your own code.
 .TP
 Retrieving An Interpreter From A Data Structure
 When an interpreter is retrieved from a data structure (e.g. the client
 data of a callback) for use in \fBTcl_Eval\fR, \fBTcl_VarEval\fR,
 \fBTcl_GlobalEval\fR, \fBTcl_SetVar\fR, or \fBTcl_GetVar\fR, a pair of
 calls to \fBTcl_Preserve\fR and \fBTcl_Release\fR should be wrapped around
 all uses of the interpreter; it is unsafe to reuse the interpreter once
 \fBTcl_Release\fR has been called.  If an interpreter is stored inside a
 callback data structure, an appropriate deletion cleanup mechanism should
 be set up by the code that creates the data structure so that the
 interpreter is removed from the data structure (e.g. by setting the field
 to NULL) when the interpreter is deleted. Otherwise, you may be using an
 interpreter that has been freed and whose memory may already have been
 reused.
 .PP
 All uses of interpreters in Tcl and Tk have already been protected.
 Extension writers should ensure that their code also properly protects any
 additional interpreters used, as described above.

 .SH "SEE ALSO"
 Tcl_Preserve(3), Tcl_Release(3)

 .SH KEYWORDS
 command, create, delete, interpreter
	'\"
	'\" Copyright (c) 1989-1993 The Regents of the University of California.
	'\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
	'\"
	'\" See the file "license.terms" for information on usage and redistribution
	'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
	'\"
	'\" RCS: @(#) $Id: CrtInterp.3,v 1.7 2002/06/26 11:50:52 msofer Exp $
	'\"
	'\" The 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)
	'\"
	'\" .AS ?type? ?name?
	'\" Give maximum sizes of arguments for setting tab stops. Type and
	'\" name are examples of largest possible arguments that will be passed
	'\" to .AP later. If args are omitted, default tab stops are used.
	'\"
	'\" .BS
	'\" Start box enclosure. From here until next .BE, everything will be
	'\" enclosed in one large box.
	'\"
	'\" .BE
	'\" End of box enclosure.
	'\"
	'\" .CS
	'\" Begin code excerpt.
	'\"
	'\" .CE
	'\" End code excerpt.
	'\"
	'\" .VS ?version? ?br?
	'\" Begin vertical sidebar, for use in marking newly-changed parts
	'\" of man pages. The first argument is ignored and used for recording
	'\" the version when the .VS was added, so that the sidebars can be
	'\" found and removed when they reach a certain age. If another argument
	'\" is present, then a line break is forced before starting the sidebar.
	'\"
	'\" .VE
	'\" End of vertical sidebar.
	'\"
	'\" .DS
	'\" Begin an indented unfilled display.
	'\"
	'\" .DE
	'\" End of indented unfilled display.
	'\"
	'\" .SO
	'\" Start of list of standard options for a Tk widget. The
	'\" options follow on successive lines, in four columns separated
	'\" by tabs.
	'\"
	'\" .SE
	'\" End of list of standard options for a Tk widget.
	'\"
	'\" .OP cmdName dbName dbClass
	'\" Start of description of a specific option. cmdName gives the
	'\" option's name as specified in the class command, dbName gives
	'\" the option's name in the option database, and dbClass gives
	'\" the option's class in the option database.
	'\"
	'\" .UL arg1 arg2
	'\" Print arg1 underlined, then print arg2 normally.
	'\"
	'\" RCS: @(#) $Id: man.macros,v 1.4 2000/08/25 06:18:32 ericm Exp $
	'\"
	'\" # 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
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	.el \{\
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	..
	'\" # 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
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	.if n .fi
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	.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)
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	.el .nr ^v 1u
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	.de VE
	.ie n 'mc
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	.sp -1
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	.\}
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	'\" # box/sidebar if in box/sidebar mode, then invoked standard
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	.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
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	'fi
	.ev
	.if \\n(^b \{\
	.mk ^y
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	.\}
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	.de DE
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	.de SO
	.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 \\fBoptions\\fR 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
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	.nf
	.ta .25i .5i .75i 1i
	..
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	.de CE
	.fi
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	..
	.de UL
	\\$1\l'\|0\(ul'\\$2
	..
	.TH Tcl_CreateInterp 3 7.5 Tcl "Tcl Library Procedures"
	.BS
	.SH NAME
	Tcl_CreateInterp, Tcl_DeleteInterp, Tcl_InterpDeleted \- create and delete Tcl command interpreters
	.SH SYNOPSIS
	.nf
	\fB#include <tcl.h>\fR
	.sp
	Tcl_Interp *
	\fBTcl_CreateInterp\fR()
	.sp
	\fBTcl_DeleteInterp\fR(\fIinterp\fR)
	.sp
	int
	\fBTcl_InterpDeleted\fR(\fIinterp\fR)
	.SH ARGUMENTS
	.AS Tcl_Interp *interp
	.AP Tcl_Interp *interp in
	Token for interpreter to be destroyed.
	.BE

	.SH DESCRIPTION
	.PP
	\fBTcl_CreateInterp\fR creates a new interpreter structure and returns
	a token for it. The token is required in calls to most other Tcl
	procedures, such as \fBTcl_CreateCommand\fR, \fBTcl_Eval\fR, and
	\fBTcl_DeleteInterp\fR.
	Clients are only allowed to access a few of the fields of
	Tcl_Interp structures; see the \fBTcl_Interp\fR
	and \fBTcl_CreateCommand\fR man pages for details.
	The new interpreter is initialized with the built-in Tcl commands
	and with the variables documented in tclvars(n). To bind in
	additional commands, call \fBTcl_CreateCommand\fR.
	.PP
	\fBTcl_DeleteInterp\fR marks an interpreter as deleted; the interpreter
	will eventually be deleted when all calls to \fBTcl_Preserve\fR for it have
	been matched by calls to \fBTcl_Release\fR. At that time, all of the
	resources associated with it, including variables, procedures, and
	application-specific command bindings, will be deleted. After
	\fBTcl_DeleteInterp\fR returns any attempt to use \fBTcl_Eval\fR on the
	interpreter will fail and return \fBTCL_ERROR\fR. After the call to
	\fBTcl_DeleteInterp\fR it is safe to examine the interpreter's result,
	query or set the values of variables, define, undefine or retrieve
	procedures, and examine the runtime evaluation stack. See below, in the
	section \fBINTERPRETERS AND MEMORY MANAGEMENT\fR for details.
	.PP
	\fBTcl_InterpDeleted\fR returns nonzero if \fBTcl_DeleteInterp\fR was
	called with \fIinterp\fR as its argument; this indicates that the
	interpreter will eventually be deleted, when the last call to
	\fBTcl_Preserve\fR for it is matched by a call to \fBTcl_Release\fR. If
	nonzero is returned, further calls to \fBTcl_Eval\fR in this interpreter
	will return \fBTCL_ERROR\fR.
	.PP
	\fBTcl_InterpDeleted\fR is useful in deletion callbacks to distinguish
	between when only the memory the callback is responsible for is being
	deleted and when the whole interpreter is being deleted. In the former case
	the callback may recreate the data being deleted, but this would lead to an
	infinite loop if the interpreter were being deleted.

	.SH "INTERPRETERS AND MEMORY MANAGEMENT"
	.PP
	\fBTcl_DeleteInterp\fR can be called at any time on an interpreter that may
	be used by nested evaluations and C code in various extensions. Tcl
	implements a simple mechanism that allows callers to use interpreters
	without worrying about the interpreter being deleted in a nested call, and
	without requiring special code to protect the interpreter, in most cases.
	This mechanism ensures that nested uses of an interpreter can safely
	continue using it even after \fBTcl_DeleteInterp\fR is called.
	.PP
	The mechanism relies on matching up calls to \fBTcl_Preserve\fR with calls
	to \fBTcl_Release\fR. If \fBTcl_DeleteInterp\fR has been called, only when
	the last call to \fBTcl_Preserve\fR is matched by a call to
	\fBTcl_Release\fR, will the interpreter be freed. See the manual entry for
	\fBTcl_Preserve\fR for a description of these functions.
	.PP
	The rules for when the user of an interpreter must call \fBTcl_Preserve\fR
	and \fBTcl_Release\fR are simple:
	.TP
	Interpreters Passed As Arguments
	Functions that are passed an interpreter as an argument can safely use the
	interpreter without any special protection. Thus, when you write an
	extension consisting of new Tcl commands, no special code is needed to
	protect interpreters received as arguments. This covers the majority of all
	uses.
	.TP
	Interpreter Creation And Deletion
	When a new interpreter is created and used in a call to \fBTcl_Eval\fR,
	\fBTcl_VarEval\fR, \fBTcl_GlobalEval\fR, \fBTcl_SetVar\fR, or
	\fBTcl_GetVar\fR, a pair of calls to \fBTcl_Preserve\fR and
	\fBTcl_Release\fR should be wrapped around all uses of the interpreter.
	Remember that it is unsafe to use the interpreter once \fBTcl_Release\fR
	has been called. To ensure that the interpreter is properly deleted when
	it is no longer needed, call \fBTcl_InterpDeleted\fR to test if some other
	code already called \fBTcl_DeleteInterp\fR; if not, call
	\fBTcl_DeleteInterp\fR before calling \fBTcl_Release\fR in your own code.
	.TP
	Retrieving An Interpreter From A Data Structure
	When an interpreter is retrieved from a data structure (e.g. the client
	data of a callback) for use in \fBTcl_Eval\fR, \fBTcl_VarEval\fR,
	\fBTcl_GlobalEval\fR, \fBTcl_SetVar\fR, or \fBTcl_GetVar\fR, a pair of
	calls to \fBTcl_Preserve\fR and \fBTcl_Release\fR should be wrapped around
	all uses of the interpreter; it is unsafe to reuse the interpreter once
	\fBTcl_Release\fR has been called. If an interpreter is stored inside a
	callback data structure, an appropriate deletion cleanup mechanism should
	be set up by the code that creates the data structure so that the
	interpreter is removed from the data structure (e.g. by setting the field
	to NULL) when the interpreter is deleted. Otherwise, you may be using an
	interpreter that has been freed and whose memory may already have been
	reused.
	.PP
	All uses of interpreters in Tcl and Tk have already been protected.
	Extension writers should ensure that their code also properly protects any
	additional interpreters used, as described above.

	.SH "SEE ALSO"
	Tcl_Preserve(3), Tcl_Release(3)

	.SH KEYWORDS
	command, create, delete, interpreter