'\" '\" Copyright (c) 1993 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: fcopy.n,v 1.1.1.2 2009/03/23 15:10:43 duncan 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 1.1.1.1 2007/07/10 15:04:23 duncan 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 fcopy n 8.0 Tcl "Tcl Built-In Commands" .BS '\" Note: do not modify the .SH NAME line immediately below! .SH NAME fcopy \- Copy data from one channel to another. .SH SYNOPSIS \fBfcopy \fIinchan\fR \fIoutchan\fR ?\fB\-size \fIsize\fR? ?\fB\-command \fIcallback\fR? .BE .SH DESCRIPTION .PP The \fBfcopy\fP command copies data from one I/O channel, \fIinchan\fR to another I/O channel, \fIoutchan\fR. The \fBfcopy\fP command leverages the buffering in the Tcl I/O system to avoid extra copies and to avoid buffering too much data in main memory when copying large files to slow destinations like network sockets. .PP The \fBfcopy\fP command transfers data from \fIinchan\fR until end of file or \fIsize\fP bytes have been transferred. If no \fB\-size\fP argument is given, then the copy goes until end of file. All the data read from \fIinchan\fR is copied to \fIoutchan\fR. Without the \fB\-command\fP option, \fBfcopy\fP blocks until the copy is complete and returns the number of bytes written to \fIoutchan\fR. .PP The \fB\-command\fP argument makes \fBfcopy\fP work in the background. In this case it returns immediately and the \fIcallback\fP is invoked later when the copy completes. The \fIcallback\fP is called with one or two additional arguments that indicates how many bytes were written to \fIoutchan\fR. If an error occurred during the background copy, the second argument is the error string associated with the error. With a background copy, it is not necessary to put \fIinchan\fR or \fIoutchan\fR into non-blocking mode; the \fBfcopy\fP command takes care of that automatically. However, it is necessary to enter the event loop by using the \fBvwait\fP command or by using Tk. .PP You are not allowed to do other I/O operations with \fIinchan\fR or \fIoutchan\fR during a background fcopy. If either \fIinchan\fR or \fIoutchan\fR get closed while the copy is in progress, the current copy is stopped and the command callback is \fInot\fP made. If \fIinchan\fR is closed, then all data already queued for \fIoutchan\fR is written out. .PP Note that \fIinchan\fR can become readable during a background copy. You should turn off any \fBfileevent\fP handlers during a background copy so those handlers do not interfere with the copy. Any I/O attempted by a \fBfileevent\fP handler will get a "channel busy" error. .PP \fBFcopy\fR translates end-of-line sequences in \fIinchan\fR and \fIoutchan\fR according to the \fB\-translation\fR option for these channels. See the manual entry for \fBfconfigure\fR for details on the \fB\-translation\fR option. The translations mean that the number of bytes read from \fIinchan\fR can be different than the number of bytes written to \fIoutchan\fR. Only the number of bytes written to \fIoutchan\fR is reported, either as the return value of a synchronous \fBfcopy\fP or as the argument to the callback for an asynchronous \fBfcopy\fP. .PP \fBFcopy\fR obeys the encodings configured for the channels. This means that the incoming characters are converted internally first UTF-8 and then into the encoding of the channel \fBfcopy\fR writes to. See the manual entry for \fBfconfigure\fR for details on the \fB\-encoding\fR option. No conversion is done if both channels are set to encoding "binary". If only the output channel is set to encoding "binary" the system will write the internal UTF-8 representation of the incoming characters. If only the input channel is set to encoding "binary" the system will assume that the incoming bytes are valid UTF-8 characters and convert them according to the output encoding. The behaviour of the system for bytes which are not valid UTF-8 characters is undefined in this case. .SH EXAMPLE .PP This first example shows how the callback gets passed the number of bytes transferred. It also uses vwait to put the application into the event loop. Of course, this simplified example could be done without the command callback. .DS proc Cleanup {in out bytes {error {}}} { global total set total $bytes close $in close $out if {[string length $error] != 0} { # error occurred during the copy } } set in [open $file1] set out [socket $server $port] fcopy $in $out -command [list Cleanup $in $out] vwait total .DE .PP The second example copies in chunks and tests for end of file in the command callback .DS proc CopyMore {in out chunk bytes {error {}}} { global total done incr total $bytes if {([string length $error] != 0) || [eof $in]} { set done $total close $in close $out } else { fcopy $in $out -command [list CopyMore $in $out $chunk] \\ -size $chunk } } set in [open $file1] set out [socket $server $port] set chunk 1024 set total 0 fcopy $in $out -command [list CopyMore $in $out $chunk] -size $chunk vwait done .DE .SH "SEE ALSO" eof(n), fblocked(n), fconfigure(n) .SH KEYWORDS blocking, channel, end of line, end of file, nonblocking, read, translation