| '\" |
| '\" 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 |
| .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 |
| .. |
| '\" # 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 |
| .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 |
| .. |
| '\" # 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 |
| '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 |
| .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 |