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

 '\"
 '\" Copyright (c) 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: LinkVar.3,v 1.6 2002/08/05 03:24:39 dgp 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
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 '\"	Begin vertical sidebar, for use in marking newly-changed parts
 '\"	of man pages.  The first argument is ignored and used for recording
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 '\" .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
 .\}
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 \&\\fI\\$1\\fP
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 .nr )C \\n()Bu+\\w'(in/out)'u+2n
 ..
 .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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 .el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c
 .\}
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 .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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 .LP
 .nf
 .ta 5.5c 11c
 .ft B
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 '\"	# 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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 .TH Tcl_LinkVar 3 7.5 Tcl "Tcl Library Procedures"
 .BS
 .SH NAME
 Tcl_LinkVar, Tcl_UnlinkVar, Tcl_UpdateLinkedVar \- link Tcl variable to C variable
 .SH SYNOPSIS
 .nf
 \fB#include <tcl.h>\fR
 .sp
 int
 \fBTcl_LinkVar\fR(\fIinterp, varName, addr, type\fR)
 .sp
 \fBTcl_UnlinkVar\fR(\fIinterp, varName\fR)
 .sp
 \fBTcl_UpdateLinkedVar\fR(\fIinterp, varName\fR)
 .SH ARGUMENTS
 .AS Tcl_Interp writable
 .AP Tcl_Interp *interp in
 Interpreter that contains \fIvarName\fR.
 Also used by \fBTcl_LinkVar\fR to return error messages.
 .AP "CONST char" *varName in
 Name of global variable.
 .AP char *addr in
 Address of C variable that is to be linked to \fIvarName\fR.
 .AP int type in
 Type of C variable.  Must be one of TCL_LINK_INT, TCL_LINK_DOUBLE,
 .VS 8.4
 TCL_LINK_WIDE_INT,
 .VE 8.4
 TCL_LINK_BOOLEAN, or TCL_LINK_STRING, optionally OR'ed with
 TCL_LINK_READ_ONLY to make Tcl variable read-only.
 .BE

 .SH DESCRIPTION
 .PP
 \fBTcl_LinkVar\fR uses variable traces to keep the Tcl variable
 named by \fIvarName\fR in sync with the C variable at the address
 given by \fIaddr\fR.
 Whenever the Tcl variable is read the value of the C variable will
 be returned, and whenever the Tcl variable is written the C
 variable will be updated to have the same value.
 \fBTcl_LinkVar\fR normally returns TCL_OK;  if an error occurs
 while setting up the link (e.g. because \fIvarName\fR is the
 name of array) then TCL_ERROR is returned and the interpreter's result
 contains an error message.
 .PP
 The \fItype\fR argument specifies the type of the C variable,
 and must have one of the following values, optionally OR'ed with
 TCL_LINK_READ_ONLY:
 .TP
 \fBTCL_LINK_INT\fR
 The C variable is of type \fBint\fR.
 Any value written into the Tcl variable must have a proper integer
 form acceptable to \fBTcl_GetIntFromObj\fR;  attempts to write
 non-integer values into \fIvarName\fR will be rejected with
 Tcl errors.
 .TP
 \fBTCL_LINK_DOUBLE\fR
 The C variable is of type \fBdouble\fR.
 Any value written into the Tcl variable must have a proper real
 form acceptable to \fBTcl_GetDoubleFromObj\fR;  attempts to write
 non-real values into \fIvarName\fR will be rejected with
 Tcl errors.
 .TP
 \fBTCL_LINK_WIDE_INT\fR
 .VS 8.4
 The C variable is of type \fBTcl_WideInt\fR (which is an integer type
 at least 64-bits wide on all platforms that can support it.)
 Any value written into the Tcl variable must have a proper integer
 form acceptable to \fBTcl_GetWideIntFromObj\fR;  attempts to write
 non-integer values into \fIvarName\fR will be rejected with
 Tcl errors.
 .VE 8.4
 .TP
 \fBTCL_LINK_BOOLEAN\fR
 The C variable is of type \fBint\fR.
 If its value is zero then it will read from Tcl as ``0'';
 otherwise it will read from Tcl as ``1''.
 Whenever \fIvarName\fR is
 modified, the C variable will be set to a 0 or 1 value.
 Any value written into the Tcl variable must have a proper boolean
 form acceptable to \fBTcl_GetBooleanFromObj\fR;  attempts to write
 non-boolean values into \fIvarName\fR will be rejected with
 Tcl errors.
 .TP
 \fBTCL_LINK_STRING\fR
 The C variable is of type \fBchar *\fR.
 .VS
 If its value is not null then it must be a pointer to a string
 allocated with \fBTcl_Alloc\fR or \fBckalloc\fR.
 .VE
 Whenever the Tcl variable is modified the current C string will be
 freed and new memory will be allocated to hold a copy of the variable's
 new value.
 If the C variable contains a null pointer then the Tcl variable
 will read as ``NULL''.
 .PP
 If the TCL_LINK_READ_ONLY flag is present in \fItype\fR then the
 variable will be read-only from Tcl, so that its value can only be
 changed by modifying the C variable.
 Attempts to write the variable from Tcl will be rejected with errors.
 .PP
 \fBTcl_UnlinkVar\fR removes the link previously set up for the
 variable given by \fIvarName\fR.  If there does not exist a link
 for \fIvarName\fR then the procedure has no effect.
 .PP
 \fBTcl_UpdateLinkedVar\fR may be invoked after the C variable has
 changed to force the Tcl variable to be updated immediately.
 In many cases this procedure is not needed, since any attempt to
 read the Tcl variable will return the latest value of the C variable.
 However, if a trace has been set on the Tcl variable (such as a
 Tk widget that wishes to display the value of the variable), the
 trace will not trigger when the C variable has changed.
 \fBTcl_UpdateLinkedVar\fR ensures that any traces on the Tcl
 variable are invoked.

 .SH KEYWORDS
 boolean, integer, link, read-only, real, string, traces, variable
	'\"
	'\" Copyright (c) 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: LinkVar.3,v 1.6 2002/08/05 03:24:39 dgp 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
	.\}
	.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
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	.if n .ti 0
	.if n \l'\\n(.lu\(ul'
	.if n .fi
	..
	'\" # BE - end boxed text (draw box now)
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	.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
	..
	'\" # VS - start vertical sidebar
	'\" # ^Y = starting y location
	'\" # ^v = 1 (for troff; for nroff this doesn't matter)
	.de VS
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	.mk ^Y
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	.el .nr ^v 1u
	..
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	.de VE
	.ie n 'mc
	.el \{\
	.ev 2
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	.ti 0
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	\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
	..
	'\" # Special macro to handle page bottom: finish off current
	'\" # box/sidebar if in box/sidebar mode, then invoked standard
	'\" # page bottom macro.
	.de ^B
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	'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
	.\}
	..
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	.de DS
	.RS
	.nf
	.sp
	..
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	.de DE
	.fi
	.RE
	.sp
	..
	'\" # SO - start of list of standard options
	.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
	..
	'\" # CS - begin code excerpt
	.de CS
	.RS
	.nf
	.ta .25i .5i .75i 1i
	..
	'\" # CE - end code excerpt
	.de CE
	.fi
	.RE
	..
	.de UL
	\\$1\l'\|0\(ul'\\$2
	..
	.TH Tcl_LinkVar 3 7.5 Tcl "Tcl Library Procedures"
	.BS
	.SH NAME
	Tcl_LinkVar, Tcl_UnlinkVar, Tcl_UpdateLinkedVar \- link Tcl variable to C variable
	.SH SYNOPSIS
	.nf
	\fB#include <tcl.h>\fR
	.sp
	int
	\fBTcl_LinkVar\fR(\fIinterp, varName, addr, type\fR)
	.sp
	\fBTcl_UnlinkVar\fR(\fIinterp, varName\fR)
	.sp
	\fBTcl_UpdateLinkedVar\fR(\fIinterp, varName\fR)
	.SH ARGUMENTS
	.AS Tcl_Interp writable
	.AP Tcl_Interp *interp in
	Interpreter that contains \fIvarName\fR.
	Also used by \fBTcl_LinkVar\fR to return error messages.
	.AP "CONST char" *varName in
	Name of global variable.
	.AP char *addr in
	Address of C variable that is to be linked to \fIvarName\fR.
	.AP int type in
	Type of C variable. Must be one of TCL_LINK_INT, TCL_LINK_DOUBLE,
	.VS 8.4
	TCL_LINK_WIDE_INT,
	.VE 8.4
	TCL_LINK_BOOLEAN, or TCL_LINK_STRING, optionally OR'ed with
	TCL_LINK_READ_ONLY to make Tcl variable read-only.
	.BE

	.SH DESCRIPTION
	.PP
	\fBTcl_LinkVar\fR uses variable traces to keep the Tcl variable
	named by \fIvarName\fR in sync with the C variable at the address
	given by \fIaddr\fR.
	Whenever the Tcl variable is read the value of the C variable will
	be returned, and whenever the Tcl variable is written the C
	variable will be updated to have the same value.
	\fBTcl_LinkVar\fR normally returns TCL_OK; if an error occurs
	while setting up the link (e.g. because \fIvarName\fR is the
	name of array) then TCL_ERROR is returned and the interpreter's result
	contains an error message.
	.PP
	The \fItype\fR argument specifies the type of the C variable,
	and must have one of the following values, optionally OR'ed with
	TCL_LINK_READ_ONLY:
	.TP
	\fBTCL_LINK_INT\fR
	The C variable is of type \fBint\fR.
	Any value written into the Tcl variable must have a proper integer
	form acceptable to \fBTcl_GetIntFromObj\fR; attempts to write
	non-integer values into \fIvarName\fR will be rejected with
	Tcl errors.
	.TP
	\fBTCL_LINK_DOUBLE\fR
	The C variable is of type \fBdouble\fR.
	Any value written into the Tcl variable must have a proper real
	form acceptable to \fBTcl_GetDoubleFromObj\fR; attempts to write
	non-real values into \fIvarName\fR will be rejected with
	Tcl errors.
	.TP
	\fBTCL_LINK_WIDE_INT\fR
	.VS 8.4
	The C variable is of type \fBTcl_WideInt\fR (which is an integer type
	at least 64-bits wide on all platforms that can support it.)
	Any value written into the Tcl variable must have a proper integer
	form acceptable to \fBTcl_GetWideIntFromObj\fR; attempts to write
	non-integer values into \fIvarName\fR will be rejected with
	Tcl errors.
	.VE 8.4
	.TP
	\fBTCL_LINK_BOOLEAN\fR
	The C variable is of type \fBint\fR.
	If its value is zero then it will read from Tcl as ``0'';
	otherwise it will read from Tcl as ``1''.
	Whenever \fIvarName\fR is
	modified, the C variable will be set to a 0 or 1 value.
	Any value written into the Tcl variable must have a proper boolean
	form acceptable to \fBTcl_GetBooleanFromObj\fR; attempts to write
	non-boolean values into \fIvarName\fR will be rejected with
	Tcl errors.
	.TP
	\fBTCL_LINK_STRING\fR
	The C variable is of type \fBchar *\fR.
	.VS
	If its value is not null then it must be a pointer to a string
	allocated with \fBTcl_Alloc\fR or \fBckalloc\fR.
	.VE
	Whenever the Tcl variable is modified the current C string will be
	freed and new memory will be allocated to hold a copy of the variable's
	new value.
	If the C variable contains a null pointer then the Tcl variable
	will read as ``NULL''.
	.PP
	If the TCL_LINK_READ_ONLY flag is present in \fItype\fR then the
	variable will be read-only from Tcl, so that its value can only be
	changed by modifying the C variable.
	Attempts to write the variable from Tcl will be rejected with errors.
	.PP
	\fBTcl_UnlinkVar\fR removes the link previously set up for the
	variable given by \fIvarName\fR. If there does not exist a link
	for \fIvarName\fR then the procedure has no effect.
	.PP
	\fBTcl_UpdateLinkedVar\fR may be invoked after the C variable has
	changed to force the Tcl variable to be updated immediately.
	In many cases this procedure is not needed, since any attempt to
	read the Tcl variable will return the latest value of the C variable.
	However, if a trace has been set on the Tcl variable (such as a
	Tk widget that wishes to display the value of the variable), the
	trace will not trigger when the C variable has changed.
	\fBTcl_UpdateLinkedVar\fR ensures that any traces on the Tcl
	variable are invoked.

	.SH KEYWORDS
	boolean, integer, link, read-only, real, string, traces, variable