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

 '\"
 '\" Copyright (c) 1990-1994 The Regents of the University of California.
 '\" Copyright (c) 1994-1997 Sun Microsystems, Inc.
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 '\" RCS: @(#) $Id: CrtFileHdlr.3,v 1.2 1998/09/14 18:39:47 stanton 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,
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 '\"	needed;  use .AS below instead)
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 '\"	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.
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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
 '\"	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
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 \&\\fI\\$1\\fP
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 .\}
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 .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
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 \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'
 .\}
 .\}
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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
 .\}
 .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
 .\}
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 .LP
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 .ta 5.5c 11c
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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
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 .de UL
 \\$1\l'|0\(ul'\\$2
 ..
 .TH Tcl_CreateFileHandler 3 8.0 Tcl "Tcl Library Procedures"
 .BS
 .SH NAME
 Tcl_CreateFileHandler, Tcl_DeleteFileHandler \- associate procedure callbacks with files or devices (Unix only)
 .SH SYNOPSIS
 .nf
 \fB#include <tcl.h>\fR
 .VS
 .sp
 \fBTcl_CreateFileHandler\fR(\fIfd, mask, proc, clientData\fR)
 .sp
 \fBTcl_DeleteFileHandler\fR(\fIfd\fR)
 .VE
 .SH ARGUMENTS
 .AS Tcl_FileProc clientData
 .VS
 .AP int fd in
 Unix file descriptor for an open file or device.
 .VE
 .AP int mask in
 Conditions under which \fIproc\fR should be called:
 OR-ed combination of \fBTCL_READABLE\fR, \fBTCL_WRITABLE\fR,
 and \fBTCL_EXCEPTION\fR.  May be set to 0 to temporarily disable
 a handler.
 .AP Tcl_FileProc *proc in
 Procedure to invoke whenever the file or device indicated
 by \fIfile\fR meets the conditions specified by \fImask\fR.
 .AP ClientData clientData in
 Arbitrary one-word value to pass to \fIproc\fR.
 .BE

 .SH DESCRIPTION
 .PP
 .VS
 \fBTcl_CreateFileHandler\fR arranges for \fIproc\fR to be
 invoked in the future whenever I/O becomes possible on a file
 or an exceptional condition exists for the file.  The file
 is indicated by \fIfd\fR, and the conditions of interest
 .VE
 are indicated by \fImask\fR.  For example, if \fImask\fR
 is \fBTCL_READABLE\fR, \fIproc\fR will be called when
 the file is readable.
 The callback to \fIproc\fR is made by \fBTcl_DoOneEvent\fR, so
 \fBTcl_CreateFileHandler\fR is only useful in programs that dispatch
 events through \fBTcl_DoOneEvent\fR or through Tcl commands such
 as \fBvwait\fR.
 .PP
 \fIProc\fR should have arguments and result that match the
 type \fBTcl_FileProc\fR:
 .CS
 typedef void Tcl_FileProc(
 	ClientData \fIclientData\fR,
 	int \fImask\fR);
 .CE
 The \fIclientData\fR parameter to \fIproc\fR is a copy
 of the \fIclientData\fR
 argument given to \fBTcl_CreateFileHandler\fR when the callback
 was created.  Typically, \fIclientData\fR points to a data
 structure containing application-specific information about
 the file.  \fIMask\fR is an integer mask indicating which
 of the requested conditions actually exists for the file;  it
 will contain a subset of the bits in the \fImask\fR argument
 to \fBTcl_CreateFileHandler\fR.
 .PP
 .PP
 There may exist only one handler for a given file at a given time.
 If \fBTcl_CreateFileHandler\fR is called when a handler already
 exists for \fIfd\fR, then the new callback replaces the information
 that was previously recorded.
 .PP
 \fBTcl_DeleteFileHandler\fR may be called to delete the
 file handler for \fIfd\fR;  if no handler exists for the
 file given by \fIfd\fR then the procedure has no effect.
 .PP
 The purpose of file handlers is to enable an application to respond to
 events while waiting for files to become ready for I/O.  For this to work
 correctly, the application may need to use non-blocking I/O operations on
 the files for which handlers are declared.  Otherwise the application may
 block if it reads or writes too much data; while waiting for the I/O to
 complete the application won't be able to service other events. Use
 \fBTcl_SetChannelOption\fR with \fB\-blocking\fR to set the channel into
 blocking or nonblocking mode as required.
 .PP
 .VS
 Note that these interfaces are only supported by the Unix
 implementation of the Tcl notifier.
 .VE

 .SH KEYWORDS
 callback, file, handler
	'\"
	'\" Copyright (c) 1990-1994 The Regents of the University of California.
	'\" Copyright (c) 1994-1997 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: CrtFileHdlr.3,v 1.2 1998/09/14 18:39:47 stanton 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
	..
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	.de VE
	.ie n 'mc
	.el \{\
	.ev 2
	.nf
	.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
	.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
	.\}
	..
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	.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_CreateFileHandler 3 8.0 Tcl "Tcl Library Procedures"
	.BS
	.SH NAME
	Tcl_CreateFileHandler, Tcl_DeleteFileHandler \- associate procedure callbacks with files or devices (Unix only)
	.SH SYNOPSIS
	.nf
	\fB#include <tcl.h>\fR
	.VS
	.sp
	\fBTcl_CreateFileHandler\fR(\fIfd, mask, proc, clientData\fR)
	.sp
	\fBTcl_DeleteFileHandler\fR(\fIfd\fR)
	.VE
	.SH ARGUMENTS
	.AS Tcl_FileProc clientData
	.VS
	.AP int fd in
	Unix file descriptor for an open file or device.
	.VE
	.AP int mask in
	Conditions under which \fIproc\fR should be called:
	OR-ed combination of \fBTCL_READABLE\fR, \fBTCL_WRITABLE\fR,
	and \fBTCL_EXCEPTION\fR. May be set to 0 to temporarily disable
	a handler.
	.AP Tcl_FileProc *proc in
	Procedure to invoke whenever the file or device indicated
	by \fIfile\fR meets the conditions specified by \fImask\fR.
	.AP ClientData clientData in
	Arbitrary one-word value to pass to \fIproc\fR.
	.BE

	.SH DESCRIPTION
	.PP
	.VS
	\fBTcl_CreateFileHandler\fR arranges for \fIproc\fR to be
	invoked in the future whenever I/O becomes possible on a file
	or an exceptional condition exists for the file. The file
	is indicated by \fIfd\fR, and the conditions of interest
	.VE
	are indicated by \fImask\fR. For example, if \fImask\fR
	is \fBTCL_READABLE\fR, \fIproc\fR will be called when
	the file is readable.
	The callback to \fIproc\fR is made by \fBTcl_DoOneEvent\fR, so
	\fBTcl_CreateFileHandler\fR is only useful in programs that dispatch
	events through \fBTcl_DoOneEvent\fR or through Tcl commands such
	as \fBvwait\fR.
	.PP
	\fIProc\fR should have arguments and result that match the
	type \fBTcl_FileProc\fR:
	.CS
	typedef void Tcl_FileProc(
	ClientData \fIclientData\fR,
	int \fImask\fR);
	.CE
	The \fIclientData\fR parameter to \fIproc\fR is a copy
	of the \fIclientData\fR
	argument given to \fBTcl_CreateFileHandler\fR when the callback
	was created. Typically, \fIclientData\fR points to a data
	structure containing application-specific information about
	the file. \fIMask\fR is an integer mask indicating which
	of the requested conditions actually exists for the file; it
	will contain a subset of the bits in the \fImask\fR argument
	to \fBTcl_CreateFileHandler\fR.
	.PP
	.PP
	There may exist only one handler for a given file at a given time.
	If \fBTcl_CreateFileHandler\fR is called when a handler already
	exists for \fIfd\fR, then the new callback replaces the information
	that was previously recorded.
	.PP
	\fBTcl_DeleteFileHandler\fR may be called to delete the
	file handler for \fIfd\fR; if no handler exists for the
	file given by \fIfd\fR then the procedure has no effect.
	.PP
	The purpose of file handlers is to enable an application to respond to
	events while waiting for files to become ready for I/O. For this to work
	correctly, the application may need to use non-blocking I/O operations on
	the files for which handlers are declared. Otherwise the application may
	block if it reads or writes too much data; while waiting for the I/O to
	complete the application won't be able to service other events. Use
	\fBTcl_SetChannelOption\fR with \fB\-blocking\fR to set the channel into
	blocking or nonblocking mode as required.
	.PP
	.VS
	Note that these interfaces are only supported by the Unix
	implementation of the Tcl notifier.
	.VE

	.SH KEYWORDS
	callback, file, handler