'\"
'\" 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: read.n,v 1.2 2003/11/24 05:09:59 bbbush 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",
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'\"	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
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'\" .BS
'\"	Start box enclosure.  From here until next .BE, everything will be
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'\" .BE
'\"	End of box enclosure.
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'\"
'\" .CE
'\"	End code excerpt.
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'\" .VS ?version? ?br?
'\"	Begin vertical sidebar, for use in marking newly-changed parts
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'\" .VE
'\"	End of vertical sidebar.
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'\" .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: read.n,v 1.2 2003/11/24 05:09:59 bbbush 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
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\&\\$1	\\fI\\$2\\fP	(\\$3)
.\".b
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.el \{\
.br
.ie !"\\$2"" \{\
\&\\$1	\\fI\\$2\\fP
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\&\\fI\\$1\\fP
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.\}
..
'\"	# 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
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.\}
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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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'ti 0
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.if \\n(^v \{\
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..
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.ft B
..
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.ft R
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See the \\fBoptions\\fR manual entry for details on the standard options.
..
'\"	# OP - start of full description for a single option
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Command-Line Name:	\\fB\\$1\\fR
Database Name:	\\fB\\$2\\fR
Database Class:	\\fB\\$3\\fR
.fi
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..
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.ta .25i .5i .75i 1i
..
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..
.de UL
\\$1\l'|0\(ul'\\$2
..
.TH read 3tcl 8.1 Tcl "Tcl Built-In Commands"
.BS
'\" Note:  do not modify the .SH NAME line immediately below!
.SH NAME
read \- 從一個通道讀
.SH "總覽 SYNOPSIS"
\fBread \fR?\fB\-nonewline\fR? \fIchannelId\fR
.sp
\fBread \fIchannelId numChars\fR
.BE

.SH "描述 DESCRIPTION"
.PP
在第一種形式下，\fBread\fR 命令從 \fIchannelId\fR 讀出直到文件結束的所有數據。如果指定了 \fB-nonewline\fR 開關，那麼文件的最後一個字符要是換行的話則丟棄它。
.VS 8.1
在第二種情況下，額外的參數指定要讀多少個字符。 實際上就讀取並返回這麼多字符，除非在文件中剩下的字符少於 \fInumChars\fR ；在這種情況下返回所有剩餘的字符。如果通道被配置成使用多字節編碼，則讀的字符數可能與讀的字節數不相同。
.PP
如果 \fIchannelId\fR 在非阻塞模式下，這個命令讀的字符可能不象要求的那樣多: 一旦所有可獲得的輸入已經被讀取了，這個命令將返回這些可獲得的數據，而不是爲得到更多數據而阻塞。如果通道被配置成使用多字節編碼，則實際上可能有一些字節因爲不能形成一個完整的字符而保留在內部緩衝區中。一直等到可獲得一個完整的字符或到達文件結束，此前不返回這些字節。
.VE 8.1
如果命令在到達文件結束之前返回則忽略 \fB-nonewline\fR 開關。
.PP
\fBRead\fR 依照給通道的 \fB-translation\fR 選項把輸入中的行結束轉換成換行字符。參見 \fBfconfigure\fR 手冊條目來得到關於 \fBfconfigure\fR 如何改變輸入的一個討論。

.SH "參見 SEE ALSO"
file(n), eof(n), fblocked(n), fconfigure(n)

.SH "關鍵字 KEYWORDS"
blocking, channel, end of line, end of file, nonblocking, read, translation, encoding

.SH "[中文版維護人]"
.B 寒蟬退士
.SH "[中文版最新更新]"
.B 2001/10/18
.SH "《中國 Linux 論壇 man 手冊頁翻譯計劃》:"
.BI http://cmpp.linuxforum.net
.SH "跋"
.br
本頁面中文版由中文 man 手冊頁計劃提供。
.br
中文 man 手冊頁計劃：\fBhttps://github.com/man-pages-zh/manpages-zh\fR