[OpenSPARC-T2-SAM] / sam-t2 / devtools / v9 / man / man3 / Tcl_UpdateLinkedVar.3

'\"
'\" 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 1.6.2.1 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
'\"	to .AP later.  If args are omitted, default tab stops are used.
'\"
'\" .BS
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'\" .SO
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'\"	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
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'\"
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.if t .wh -1.3i ^B
.nr ^l \n(.l
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.ie !"\\$4"" .TP \\$4
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.   ie !"\\$2"" .TP \\n()Cu
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.AS Tcl_Interp Tcl_CreateInterp in/out
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\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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.LP
See the \\fBoptions\\fR manual entry for details on the standard options.
..
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.LP
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Command-Line Name:	\\fB\\$1\\fR
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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
Commit	Line	Data
920dae64 AT	1	'\"
	2	'\" Copyright (c) 1993 The Regents of the University of California.
	3	'\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
	4	'\"
	5	'\" See the file "license.terms" for information on usage and redistribution
	6	'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
	7	'\"
	8	'\" RCS: @(#) $Id: LinkVar.3,v 1.6.2.1 2003/07/18 16:56:24 dgp Exp $
	9	'\"
	10	'\" The definitions below are for supplemental macros used in Tcl/Tk
	11	'\" manual entries.
	12	'\"
	13	'\" .AP type name in/out ?indent?
	14	'\" Start paragraph describing an argument to a library procedure.
	15	'\" type is type of argument (int, etc.), in/out is either "in", "out",
	16	'\" or "in/out" to describe whether procedure reads or modifies arg,
	17	'\" and indent is equivalent to second arg of .IP (shouldn't ever be
	18	'\" needed; use .AS below instead)
	19	'\"
	20	'\" .AS ?type? ?name?
	21	'\" Give maximum sizes of arguments for setting tab stops. Type and
	22	'\" name are examples of largest possible arguments that will be passed
	23	'\" to .AP later. If args are omitted, default tab stops are used.
	24	'\"
	25	'\" .BS
	26	'\" Start box enclosure. From here until next .BE, everything will be
	27	'\" enclosed in one large box.
	28	'\"
	29	'\" .BE
	30	'\" End of box enclosure.
	31	'\"
	32	'\" .CS
	33	'\" Begin code excerpt.
	34	'\"
	35	'\" .CE
	36	'\" End code excerpt.
	37	'\"
	38	'\" .VS ?version? ?br?
	39	'\" Begin vertical sidebar, for use in marking newly-changed parts
	40	'\" of man pages. The first argument is ignored and used for recording
	41	'\" the version when the .VS was added, so that the sidebars can be
	42	'\" found and removed when they reach a certain age. If another argument
	43	'\" is present, then a line break is forced before starting the sidebar.
	44	'\"
	45	'\" .VE
	46	'\" End of vertical sidebar.
	47	'\"
	48	'\" .DS
	49	'\" Begin an indented unfilled display.
	50	'\"
	51	'\" .DE
	52	'\" End of indented unfilled display.
	53	'\"
	54	'\" .SO
	55	'\" Start of list of standard options for a Tk widget. The
	56	'\" options follow on successive lines, in four columns separated
	57	'\" by tabs.
	58	'\"
	59	'\" .SE
	60	'\" End of list of standard options for a Tk widget.
	61	'\"
	62	'\" .OP cmdName dbName dbClass
	63	'\" Start of description of a specific option. cmdName gives the
	64	'\" option's name as specified in the class command, dbName gives
65	'\" the option's name in the option database, and dbClass gives
66	'\" the option's class in the option database.
67	'\"
68	'\" .UL arg1 arg2
69	'\" Print arg1 underlined, then print arg2 normally.
70	'\"
71	'\" RCS: @(#) $Id: man.macros,v 1.4 2000/08/25 06:18:32 ericm Exp $
72	'\"
73	'\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages.
74	.if t .wh -1.3i ^B
75	.nr ^l \n(.l
76	.ad b
77	'\" # Start an argument description
78	.de AP
79	.ie !"\\$4"" .TP \\$4
80	.el \{\
81	. ie !"\\$2"" .TP \\n()Cu
82	. el .TP 15
83	.\}
84	.ta \\n()Au \\n()Bu
85	.ie !"\\$3"" \{\
86	\&\\$1 \\fI\\$2\\fP (\\$3)
87	.\".b
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107	..
108	.AS Tcl_Interp Tcl_CreateInterp in/out
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132	.\}
133	.el \}\
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175	.\" draw two sides but no top otherwise.
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177	.el \h'-1.5n'\L'\|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'\|0u'\c
178	.\}
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182	.\}
183	.bp
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203	.RE
204	.sp
205	..
206	'\" # SO - start of list of standard options
207	.de SO
208	.SH "STANDARD OPTIONS"
209	.LP
210	.nf
211	.ta 5.5c 11c
212	.ft B
213	..
214	'\" # SE - end of list of standard options
215	.de SE
216	.fi
217	.ft R
218	.LP
219	See the \\fBoptions\\fR manual entry for details on the standard options.
220	..
221	'\" # OP - start of full description for a single option
222	.de OP
223	.LP
224	.nf
225	.ta 4c
226	Command-Line Name: \\fB\\$1\\fR
227	Database Name: \\fB\\$2\\fR
228	Database Class: \\fB\\$3\\fR
229	.fi
230	.IP
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240	.fi
241	.RE
242	..
243	.de UL
244	\\$1\l'\|0\(ul'\\$2
245	..
246	.TH Tcl_LinkVar 3 7.5 Tcl "Tcl Library Procedures"
247	.BS
248	.SH NAME
249	Tcl_LinkVar, Tcl_UnlinkVar, Tcl_UpdateLinkedVar \- link Tcl variable to C variable
250	.SH SYNOPSIS
251	.nf
252	\fB#include <tcl.h>\fR
253	.sp
254	int
255	\fBTcl_LinkVar\fR(\fIinterp, varName, addr, type\fR)
256	.sp
257	\fBTcl_UnlinkVar\fR(\fIinterp, varName\fR)
258	.sp
259	\fBTcl_UpdateLinkedVar\fR(\fIinterp, varName\fR)
260	.SH ARGUMENTS
261	.AS Tcl_Interp writable
262	.AP Tcl_Interp *interp in
263	Interpreter that contains \fIvarName\fR.
264	Also used by \fBTcl_LinkVar\fR to return error messages.
265	.AP "CONST char" *varName in
266	Name of global variable.
267	.AP char *addr in
268	Address of C variable that is to be linked to \fIvarName\fR.
269	.AP int type in
270	Type of C variable. Must be one of TCL_LINK_INT, TCL_LINK_DOUBLE,
271	.VS 8.4
272	TCL_LINK_WIDE_INT,
273	.VE 8.4
274	TCL_LINK_BOOLEAN, or TCL_LINK_STRING, optionally OR'ed with
275	TCL_LINK_READ_ONLY to make Tcl variable read-only.
276	.BE
277
278	.SH DESCRIPTION
279	.PP
280	\fBTcl_LinkVar\fR uses variable traces to keep the Tcl variable
281	named by \fIvarName\fR in sync with the C variable at the address
282	given by \fIaddr\fR.
283	Whenever the Tcl variable is read the value of the C variable will
284	be returned, and whenever the Tcl variable is written the C
285	variable will be updated to have the same value.
286	\fBTcl_LinkVar\fR normally returns TCL_OK; if an error occurs
287	while setting up the link (e.g. because \fIvarName\fR is the
288	name of array) then TCL_ERROR is returned and the interpreter's result
289	contains an error message.
290	.PP
291	The \fItype\fR argument specifies the type of the C variable,
292	and must have one of the following values, optionally OR'ed with
293	TCL_LINK_READ_ONLY:
294	.TP
295	\fBTCL_LINK_INT\fR
296	The C variable is of type \fBint\fR.
297	Any value written into the Tcl variable must have a proper integer
298	form acceptable to \fBTcl_GetIntFromObj\fR; attempts to write
299	non-integer values into \fIvarName\fR will be rejected with
300	Tcl errors.
301	.TP
302	\fBTCL_LINK_DOUBLE\fR
303	The C variable is of type \fBdouble\fR.
304	Any value written into the Tcl variable must have a proper real
305	form acceptable to \fBTcl_GetDoubleFromObj\fR; attempts to write
306	non-real values into \fIvarName\fR will be rejected with
307	Tcl errors.
308	.TP
309	\fBTCL_LINK_WIDE_INT\fR
310	.VS 8.4
311	The C variable is of type \fBTcl_WideInt\fR (which is an integer type
312	at least 64-bits wide on all platforms that can support it.)
313	Any value written into the Tcl variable must have a proper integer
314	form acceptable to \fBTcl_GetWideIntFromObj\fR; attempts to write
315	non-integer values into \fIvarName\fR will be rejected with
316	Tcl errors.
317	.VE 8.4
318	.TP
319	\fBTCL_LINK_BOOLEAN\fR
320	The C variable is of type \fBint\fR.
321	If its value is zero then it will read from Tcl as ``0'';
322	otherwise it will read from Tcl as ``1''.
323	Whenever \fIvarName\fR is
324	modified, the C variable will be set to a 0 or 1 value.
325	Any value written into the Tcl variable must have a proper boolean
326	form acceptable to \fBTcl_GetBooleanFromObj\fR; attempts to write
327	non-boolean values into \fIvarName\fR will be rejected with
328	Tcl errors.
329	.TP
330	\fBTCL_LINK_STRING\fR
331	The C variable is of type \fBchar *\fR.
332	.VS
333	If its value is not NULL then it must be a pointer to a string
334	allocated with \fBTcl_Alloc\fR or \fBckalloc\fR.
335	.VE
336	Whenever the Tcl variable is modified the current C string will be
337	freed and new memory will be allocated to hold a copy of the variable's
338	new value.
339	If the C variable contains a NULL pointer then the Tcl variable
340	will read as ``NULL''.
341	.PP
342	If the TCL_LINK_READ_ONLY flag is present in \fItype\fR then the
343	variable will be read-only from Tcl, so that its value can only be
344	changed by modifying the C variable.
345	Attempts to write the variable from Tcl will be rejected with errors.
346	.PP
347	\fBTcl_UnlinkVar\fR removes the link previously set up for the
348	variable given by \fIvarName\fR. If there does not exist a link
349	for \fIvarName\fR then the procedure has no effect.
350	.PP
351	\fBTcl_UpdateLinkedVar\fR may be invoked after the C variable has
352	changed to force the Tcl variable to be updated immediately.
353	In many cases this procedure is not needed, since any attempt to
354	read the Tcl variable will return the latest value of the C variable.
355	However, if a trace has been set on the Tcl variable (such as a
356	Tk widget that wishes to display the value of the variable), the
357	trace will not trigger when the C variable has changed.
358	\fBTcl_UpdateLinkedVar\fR ensures that any traces on the Tcl
359	variable are invoked.
360
361	.SH KEYWORDS
362	boolean, integer, link, read-only, real, string, traces, variable