'\" '\" Copyright 1989 Regents of the University of California '\" Permission to use, copy, modify, and distribute this '\" documentation for any purpose and without fee is hereby '\" granted, provided that this notice appears in all copies. '\" The University of California makes no representations about '\" the suitability of this material for any purpose. It is '\" provided "as is" without express or implied warranty. '\" '\" $Header: /a/cvs/386BSD/ports/tcl-dp/man/manl/filehandler.l,v 1.1.1.1 1993/09/01 00:46:33 jkh Exp $ SPRITE (Berkeley) ' .\" The definitions below are for supplemental macros used in Sprite .\" manual entries. .\" .\" .HS name section [date [version]] .\" Replacement for .TH in other man pages. See below for valid .\" section names. .\" .\" .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. .\" .\" .VS .\" Begin vertical sidebar, for use in marking newly-changed parts .\" of man pages. .\" .\" .VE .\" End of vertical sidebar. .\" .\" .DS .\" Begin an indented unfilled display. .\" .\" .DE .\" End of indented unfilled display. .\" ' # Heading for Sprite man pages .de HS .if '\\$2'cmds' .TH \\$1 1 \\$3 \\$4 .if '\\$2'lib' .TH \\$1 3 \\$3 \\$4 .if '\\$2'tcl' .TH \\$1 3 \\$3 \\$4 .if '\\$2'tk' .TH \\$1 3 \\$3 \\$4 .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 .\} .ie !"\\$3"" \{\ .ta \\n()Au \\n()Bu \&\\$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 .. ' # 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 .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 .5 .. .de UL \\$1\l'|0\(ul'\\$2 .. .HS filehandler cmds .BS .SH NAME filehandler \- to handle file descriptor conditions .SH SYNOPSIS \fBfilehandler \fIfileId\fR ?\fImode\fR \fIcommand\fR? .BE .SH DESCRIPTION .LP The Tcl/Tk \fBfilehander\fR command allows one to specify a Tcl/Tk \fIcommand\fR which will be evaluated whenever the file descriptor represented by \fIfileId\fR is readable, writable, and/or has an exceptional condition pending. A \fIfileId\fR is an identifier which represents a file descriptor. It is identical to the identifier manipulated by the Tcl-DP (Tcl Distributed Programming) network connection management commands (\fBconnect\fR, \fBshutdown\fR, \fBsend\fR, \fBreceive\fR, etc.). \fIfileId\fR's are also manipulated by the \fBopen\fR, \fBread\fR, \fBwrite\fR, \fBgets\fR, \fBputs\fR, and \fBclose\fR file management commands of Tcl. The \fImode\fR argument indicates the situations when the \fIcommand\fR will be evaluated. It may be any combination of the following values: .RS .TP \fBr\fR Eval \fIcommand\fR whenever there is data to be read from the \fIfileId\fR. The \fIcommand\fR is evaluated with two arguments appended: \fBr\fR to indicate that data is readable on the file descriptor, and the \fIfileId\fR, which represents the file descriptor that is readable. The \fIcommand\fR should read at least some data from the \fIfileId\fR, or otherwise \fIcommand\fR will be called continuously. .TP \fBw\fR Eval \fIcommand\fR whenever data can be written to the \fIfileId\fR without blocking. The \fIcommand\fR is evaluated with two arguments appended: \fBw\fR to indicate that the file descriptor is writable, and the \fIfileId\fR, which represents the writable file descriptor. .TP \fBe\fR Eval \fIcommand\fR whenever there is an exceptional condition pending on the \fIfileId\fR. The \fIcommand\fR is evaluated with two arguments appended: \fBe\fR to indicate exception, and the \fIfileId\fR, which represents the file descriptor with the exceptional condition. .RE .PP If the \fImode\fR and \fIcommand\fR arguments are not specified, then any previously specified \fIcommand\fR for the given \fIfileId\fR is deleted. Specifying a new \fIcommand\fR using the \fBfilehandler\fR command will also delete any previously specified \fIcommand\fR for a \fIfileId\fR. .SH SEE ALSO Tcl-DP, select(2) .SH AUTHOR Pekka Nikander, Telecom Finland (Pekka.Nikander@ajk.tele.fi) .br Extended by Tim MacKenzie (tym@dibbler.cs.monash.edu.au) .br Further enhancements by Brian Smith (bsmith@cs.berkeley.edu) .br and Steve Yen (syen@cs.berkeley.edu)