'\" 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 1.6.2.1 2003/07/18 16:56:24 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
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-'\"
-'\" .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.
+.TH Tcl_LinkVar 3 7.5 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)
+.\"
+.\" .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 ?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.
+.\"
+.\" .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.
+.\"
+.\" .QW arg1 ?arg2?
+.\" Print arg1 in quotes, then arg2 normally (for trailing punctuation).
+.\"
+.\" .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
+.\" # Start an argument description
.de AP
.ie !"\\$4"" .TP \\$4
.el \{\
.\}
.ta \\n()Au \\n()Bu
.ie !"\\$3"" \{\
-\&\\$1 \\fI\\$2\\fP (\\$3)
+\&\\$1 \\fI\\$2\\fP (\\$3)
.\".b
.\}
.el \{\
.\}
.\}
..
-'\" # define tabbing values for .AP
+.\" # define tabbing values for .AP
.de AS
.nr )A 10n
.if !"\\$1"" .nr )A \\w'\\$1'u+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
+.\" # BS - start boxed text
+.\" # ^y = starting y location
+.\" # ^b = 1
.de BS
.br
.mk ^y
.if n \l'\\n(.lu\(ul'
.if n .fi
..
-'\" # BE - end boxed text (draw box now)
+.\" # BE - end boxed text (draw box now)
.de BE
.nf
.ti 0
.br
.nr ^b 0
..
-'\" # VS - start vertical sidebar
-'\" # ^Y = starting y location
-'\" # ^v = 1 (for troff; for nroff this doesn't matter)
+.\" # VS - start vertical sidebar
+.\" # ^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
+.\" # VE - end of vertical sidebar
.de VE
.ie n 'mc
.el \{\
.\}
.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.
+.\" # Special macro to handle page bottom: finish off current
+.\" # box/sidebar if in box/sidebar mode, then invoked standard
+.\" # page bottom macro.
.de ^B
.ev 2
'ti 0
.mk ^Y
.\}
..
-'\" # DS - begin display
+.\" # DS - begin display
.de DS
.RS
.nf
.sp
..
-'\" # DE - end display
+.\" # DE - end display
.de DE
.fi
.RE
.sp
..
-'\" # SO - start of list of standard options
+.\" # 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
+.\" # 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.
+See the \\*(So manual entry for details on the standard options.
..
-'\" # OP - start of full description for a single option
+.\" # OP - start of full description for a single option
.de OP
.LP
.nf
.fi
.IP
..
-'\" # CS - begin code excerpt
+.\" # CS - begin code excerpt
.de CS
.RS
.nf
.ta .25i .5i .75i 1i
..
-'\" # CE - end code excerpt
+.\" # CE - end code excerpt
.de CE
.fi
.RE
..
+.\" # UL - underline word
.de UL
\\$1\l'|0\(ul'\\$2
..
-.TH Tcl_LinkVar 3 7.5 Tcl "Tcl Library Procedures"
+.\" # 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_LinkVar, Tcl_UnlinkVar, Tcl_UpdateLinkedVar \- link Tcl variable to C variable
.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 "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.
+Type of C variable. Must be one of \fBTCL_LINK_INT\fR,
+\fBTCL_LINK_UINT\fR, \fBTCL_LINK_CHAR\fR, \fBTCL_LINK_UCHAR\fR,
+\fBTCL_LINK_SHORT\fR, \fBTCL_LINK_USHORT\fR, \fBTCL_LINK_LONG\fR,
+\fBTCL_LINK_ULONG\fR, \fBTCL_LINK_WIDE_INT\fR,
+\fBTCL_LINK_WIDE_UINT\fR, \fBTCL_LINK_FLOAT\fR,
+\fBTCL_LINK_DOUBLE\fR, \fBTCL_LINK_BOOLEAN\fR, or
+\fBTCL_LINK_STRING\fR, optionally OR'ed with \fBTCL_LINK_READ_ONLY\fR
+to make Tcl variable read-only.
.BE
-
.SH DESCRIPTION
.PP
\fBTcl_LinkVar\fR uses variable traces to keep the Tcl variable
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
+\fBTcl_LinkVar\fR normally returns \fBTCL_OK\fR; 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
+name of array) then \fBTCL_ERROR\fR 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:
+\fBTCL_LINK_READ_ONLY\fR:
.TP
\fBTCL_LINK_INT\fR
The C variable is of type \fBint\fR.
non-integer values into \fIvarName\fR will be rejected with
Tcl errors.
.TP
+\fBTCL_LINK_UINT\fR
+The C variable is of type \fBunsigned int\fR.
+Any value written into the Tcl variable must have a proper unsigned
+integer form acceptable to \fBTcl_GetWideIntFromObj\fR and in the
+platform's defined range for the \fBunsigned int\fR type; attempts to
+write non-integer values (or values outside the range) into
+\fIvarName\fR will be rejected with Tcl errors.
+.TP
+\fBTCL_LINK_CHAR\fR
+The C variable is of type \fBchar\fR.
+Any value written into the Tcl variable must have a proper integer
+form acceptable to \fBTcl_GetIntFromObj\fR and be in the range of the
+\fBchar\fR datatype; attempts to write non-integer or out-of-range
+values into \fIvarName\fR will be rejected with Tcl errors.
+.TP
+\fBTCL_LINK_UCHAR\fR
+The C variable is of type \fBunsigned char\fR.
+Any value written into the Tcl variable must have a proper unsigned
+integer form acceptable to \fBTcl_GetIntFromObj\fR and in the
+platform's defined range for the \fBunsigned char\fR type; attempts to
+write non-integer values (or values outside the range) into
+\fIvarName\fR will be rejected with Tcl errors.
+.TP
+\fBTCL_LINK_SHORT\fR
+The C variable is of type \fBshort\fR.
+Any value written into the Tcl variable must have a proper integer
+form acceptable to \fBTcl_GetIntFromObj\fR and be in the range of the
+\fBshort\fR datatype; attempts to write non-integer or out-of-range
+values into \fIvarName\fR will be rejected with Tcl errors.
+.TP
+\fBTCL_LINK_USHORT\fR
+The C variable is of type \fBunsigned short\fR.
+Any value written into the Tcl variable must have a proper unsigned
+integer form acceptable to \fBTcl_GetIntFromObj\fR and in the
+platform's defined range for the \fBunsigned short\fR type; attempts to
+write non-integer values (or values outside the range) into
+\fIvarName\fR will be rejected with Tcl errors.
+.TP
+\fBTCL_LINK_LONG\fR
+The C variable is of type \fBlong\fR.
+Any value written into the Tcl variable must have a proper integer
+form acceptable to \fBTcl_GetLongFromObj\fR; attempts to write
+non-integer or out-of-range
+values into \fIvarName\fR will be rejected with Tcl errors.
+.TP
+\fBTCL_LINK_ULONG\fR
+The C variable is of type \fBunsigned long\fR.
+Any value written into the Tcl variable must have a proper unsigned
+integer form acceptable to \fBTcl_GetWideIntFromObj\fR and in the
+platform's defined range for the \fBunsigned long\fR type; attempts to
+write non-integer values (or values outside the range) 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
non-real values into \fIvarName\fR will be rejected with
Tcl errors.
.TP
+\fBTCL_LINK_FLOAT\fR
+The C variable is of type \fBfloat\fR.
+Any value written into the Tcl variable must have a proper real
+form acceptable to \fBTcl_GetDoubleFromObj\fR and must be within the
+range acceptable for a \fBfloat\fR; attempts to
+write non-real values (or values outside the range) 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_WIDE_UINT\fR
+The C variable is of type \fBTcl_WideUInt\fR (which is an unsigned
+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 unsigned
+integer form acceptable to \fBTcl_GetWideIntFromObj\fR (it will be
+cast to unsigned);
+.\" FIXME! Use bignums instead.
+attempts to write non-integer values into \fIvarName\fR will be
+rejected with Tcl errors.
.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''.
+If its value is zero then it will read from Tcl as
+.QW 0 ;
+otherwise it will read from Tcl as
+.QW 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
.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''.
+will read as
+.QW NULL .
.PP
-If the TCL_LINK_READ_ONLY flag is present in \fItype\fR then the
+If the \fBTCL_LINK_READ_ONLY\fR 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.
trace will not trigger when the C variable has changed.
\fBTcl_UpdateLinkedVar\fR ensures that any traces on the Tcl
variable are invoked.
-
+.PP
+Note that, as with any call to a Tcl interpreter, \fBTcl_UpdateLinkedVar\fR
+must be called from the same thread that created the interpreter. The safest
+mechanism is to ensure that the C variable is only ever updated from the same
+thread that created the interpreter (possibly in response to an event posted
+with \fBTcl_ThreadQueueEvent\fR), but when it is necessary to update the
+variable in a separate thread, it is advised that \fBTcl_AsyncMark\fR be used
+to indicate to the thread hosting the interpreter that it is ready to run
+\fBTcl_UpdateLinkedVar\fR.
+.SH "SEE ALSO"
+Tcl_TraceVar(3)
.SH KEYWORDS
-boolean, integer, link, read-only, real, string, traces, variable
+boolean, integer, link, read-only, real, string, trace, variable