'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\"
-'\" RCS: @(#) $Id: OpenFileChnl.3,v 1.20.2.2 2003/10/07 15:25:46 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.
+.TH Tcl_OpenFileChannel 3 8.3 Tcl "Tcl Library Procedures"
+.\" The -*- nroff -*- 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 ?manpage?
+.\" Start of list of standard options for a Tk widget. The manpage
+.\" argument defines where to look up the standard options; if
+.\" omitted, defaults to "options". The options follow on successive
+.\" lines, in three 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.
+.\"
+.\" .QW arg1 ?arg2?
+.\" Print arg1 in quotes, then arg2 normally (for trailing punctuation).
+.\"
+.\" .PQ arg1 ?arg2?
+.\" Print an open parenthesis, arg1 in quotes, then arg2 normally
+.\" (for trailing punctuation) and then a closing parenthesis.
+.\"
+.\" # 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
+.\" # Start an argument description
.de AP
.ie !"\\$4"" .TP \\$4
.el \{\
.\}
.ta \\n()Au \\n()Bu
.ie !"\\$3"" \{\
-\&\\$1 \\fI\\$2\\fP (\\$3)
+\&\\$1 \\fI\\$2\\fP (\\$3)
.\".b
.\}
.el \{\
.\}
.\}
..
-'\" # define tabbing values for .AP
+.\" # define tabbing values for .AP
.de AS
.nr )A 10n
.if !"\\$1"" .nr )A \\w'\\$1'u+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
+.\" # BS - start boxed text
+.\" # ^y = starting y location
+.\" # ^b = 1
.de BS
.br
.mk ^y
.if n \l'\\n(.lu\(ul'
.if n .fi
..
-'\" # BE - end boxed text (draw box now)
+.\" # BE - end boxed text (draw box now)
.de BE
.nf
.ti 0
.br
.nr ^b 0
..
-'\" # VS - start vertical sidebar
-'\" # ^Y = starting y location
-'\" # ^v = 1 (for troff; for nroff this doesn't matter)
+.\" # 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
+.\" # VE - end of vertical sidebar
.de VE
.ie n 'mc
.el \{\
.\}
.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.
+.\" # 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
.mk ^Y
.\}
..
-'\" # DS - begin display
+.\" # DS - begin display
.de DS
.RS
.nf
.sp
..
-'\" # DE - end display
+.\" # DE - end display
.de DE
.fi
.RE
.sp
..
-'\" # SO - start of list of standard options
+.\" # SO - start of list of standard options
.de SO
+'ie '\\$1'' .ds So \\fBoptions\\fR
+'el .ds So \\fB\\$1\\fR
.SH "STANDARD OPTIONS"
.LP
.nf
.ta 5.5c 11c
.ft B
..
-'\" # SE - end of list of standard options
+.\" # 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.
+See the \\*(So manual entry for details on the standard options.
..
-'\" # OP - start of full description for a single option
+.\" # OP - start of full description for a single option
.de OP
.LP
.nf
.fi
.IP
..
-'\" # CS - begin code excerpt
+.\" # CS - begin code excerpt
.de CS
.RS
.nf
.ta .25i .5i .75i 1i
..
-'\" # CE - end code excerpt
+.\" # CE - end code excerpt
.de CE
.fi
.RE
..
+.\" # UL - underline word
.de UL
\\$1\l'|0\(ul'\\$2
..
-.TH Tcl_OpenFileChannel 3 8.3 Tcl "Tcl Library Procedures"
+.\" # QW - apply quotation marks to word
+.de QW
+.ie '\\*(lq'"' ``\\$1''\\$2
+.\"" fix emacs highlighting
+.el \\*(lq\\$1\\*(rq\\$2
+..
+.\" # PQ - apply parens and quotation marks to word
+.de PQ
+.ie '\\*(lq'"' (``\\$1''\\$2)\\$3
+.\"" fix emacs highlighting
+.el (\\*(lq\\$1\\*(rq\\$2)\\$3
+..
+.\" # QR - quoted range
+.de QR
+.ie '\\*(lq'"' ``\\$1''\\-``\\$2''\\$3
+.\"" fix emacs highlighting
+.el \\*(lq\\$1\\*(rq\\-\\*(lq\\$2\\*(rq\\$3
+..
+.\" # MT - "empty" string
+.de MT
+.QW ""
+..
.BS
'\" Note: do not modify the .SH NAME line immediately below!
.SH NAME
-Tcl_OpenFileChannel, Tcl_OpenCommandChannel, Tcl_MakeFileChannel, Tcl_GetChannel, Tcl_GetChannelNames, Tcl_GetChannelNamesEx, Tcl_RegisterChannel, Tcl_UnregisterChannel, Tcl_DetachChannel, Tcl_IsStandardChannel, Tcl_Close, Tcl_ReadChars, Tcl_Read, Tcl_GetsObj, Tcl_Gets, Tcl_WriteObj, Tcl_WriteChars, Tcl_Write, Tcl_Flush, Tcl_Seek, Tcl_Tell, Tcl_GetChannelOption, Tcl_SetChannelOption, Tcl_Eof, Tcl_InputBlocked, Tcl_InputBuffered, Tcl_OutputBuffered, Tcl_Ungets, Tcl_ReadRaw, Tcl_WriteRaw \- buffered I/O facilities using channels
+Tcl_OpenFileChannel, Tcl_OpenCommandChannel, Tcl_MakeFileChannel, Tcl_GetChannel, Tcl_GetChannelNames, Tcl_GetChannelNamesEx, Tcl_RegisterChannel, Tcl_UnregisterChannel, Tcl_DetachChannel, Tcl_IsStandardChannel, Tcl_Close, Tcl_ReadChars, Tcl_Read, Tcl_GetsObj, Tcl_Gets, Tcl_WriteObj, Tcl_WriteChars, Tcl_Write, Tcl_Flush, Tcl_Seek, Tcl_Tell, Tcl_TruncateChannel, Tcl_GetChannelOption, Tcl_SetChannelOption, Tcl_Eof, Tcl_InputBlocked, Tcl_InputBuffered, Tcl_OutputBuffered, Tcl_Ungets, Tcl_ReadRaw, Tcl_WriteRaw \- buffered I/O facilities using channels
.SH SYNOPSIS
.nf
\fB#include <tcl.h>\fR
.sp
Tcl_Channel
\fBTcl_GetChannel\fR(\fIinterp, channelName, modePtr\fR)
-.VS 8.3
.sp
int
\fBTcl_GetChannelNames\fR(\fIinterp\fR)
.sp
int
\fBTcl_GetChannelNamesEx\fR(\fIinterp, pattern\fR)
-.VE
.sp
void
\fBTcl_RegisterChannel\fR(\fIinterp, channel\fR)
int
\fBTcl_Close\fR(\fIinterp, channel\fR)
.sp
-.VS 8.1
int
\fBTcl_ReadChars\fR(\fIchannel, readObjPtr, charsToRead, appendFlag\fR)
.sp
.sp
int
\fBTcl_Write\fR(\fIchannel, byteBuf, bytesToWrite\fR)
-.VE
-.VS 8.3.2
.sp
int
\fBTcl_ReadRaw\fR(\fIchannel, readBuf, bytesToRead\fR)
.sp
int
\fBTcl_WriteRaw\fR(\fIchannel, byteBuf, bytesToWrite\fR)
-.VE
.sp
int
\fBTcl_Eof\fR(\fIchannel\fR)
.sp
int
\fBTcl_InputBuffered\fR(\fIchannel\fR)
-.VS 8.4
.sp
int
\fBTcl_OutputBuffered\fR(\fIchannel\fR)
-.VE
.sp
-.VS 8.4
Tcl_WideInt
\fBTcl_Seek\fR(\fIchannel, offset, seekMode\fR)
.sp
Tcl_WideInt
\fBTcl_Tell\fR(\fIchannel\fR)
-.VE 8.4
+.sp
+int
+\fBTcl_TruncateChannel\fR(\fIchannel, length\fR)
.sp
int
\fBTcl_GetChannelOption\fR(\fIinterp, channel, optionName, optionValue\fR)
\fBTcl_SetChannelOption\fR(\fIinterp, channel, optionName, newValue\fR)
.sp
.SH ARGUMENTS
-.AS Tcl_ChannelType newClientProcPtr in
+.AS Tcl_DString *channelName in/out
.AP Tcl_Interp *interp in
Used for error reporting and to look up a channel registered in it.
-.AP "CONST char" *fileName in
+.AP "const char" *fileName in
The name of a local or network file.
-.AP "CONST char" *mode in
+.AP "const char" *mode in
Specifies how the file is to be accessed. May have any of the values
allowed for the \fImode\fR argument to the Tcl \fBopen\fR command.
.AP int permissions in
permissions will be set on the created file.
.AP int argc in
The number of elements in \fIargv\fR.
-.AP "CONST char" **argv in
+.AP "const char" **argv in
Arguments for constructing a command pipeline. These values have the same
meaning as the non-switch arguments to the Tcl \fBexec\fR command.
.AP int flags in
.AP int readOrWrite in
OR-ed combination of \fBTCL_READABLE\fR and \fBTCL_WRITABLE\fR to indicate
what operations are valid on \fIhandle\fR.
-.AP "CONST char" *channelName in
+.AP "const char" *channelName in
The name of the channel.
.AP int *modePtr out
Points at an integer variable that will receive an OR-ed combination of
\fBTCL_READABLE\fR and \fBTCL_WRITABLE\fR denoting whether the channel is
open for reading and writing.
-.VS 8.3
-.AP "CONST char" *pattern in
+.AP "const char" *pattern in
The pattern to match on, passed to Tcl_StringMatch, or NULL.
-.VE
.AP Tcl_Channel channel in
A Tcl channel for input or output. Must have been the return value
from a procedure such as \fBTcl_OpenFileChannel\fR.
-.VS 8.1 br
.AP Tcl_Obj *readObjPtr in/out
-A pointer to a Tcl Object in which to store the characters read from the
+A pointer to a Tcl value in which to store the characters read from the
channel.
.AP int charsToRead in
The number of characters to read from the channel. If the channel's encoding
is \fBbinary\fR, this is equivalent to the number of bytes to read from the
channel.
.AP int appendFlag in
-If non-zero, data read from the channel will be appended to the object.
-Otherwise, the data will replace the existing contents of the object.
+If non-zero, data read from the channel will be appended to the value.
+Otherwise, the data will replace the existing contents of the value.
.AP char *readBuf out
A buffer in which to store the bytes read from the channel.
.AP int bytesToRead in
The number of bytes to read from the channel. The buffer \fIreadBuf\fR must
be large enough to hold this many bytes.
.AP Tcl_Obj *lineObjPtr in/out
-A pointer to a Tcl object in which to store the line read from the
+A pointer to a Tcl value in which to store the line read from the
channel. The line read will be appended to the current value of the
-object.
+value.
.AP Tcl_DString *lineRead in/out
A pointer to a Tcl dynamic string in which to store the line read from the
channel. Must have been initialized by the caller. The line read will be
appended to any data already in the dynamic string.
-.VS 8.3
-.AP "CONST char" *input in
+.AP "const char" *input in
The input to add to a channel buffer.
.AP int inputLen in
Length of the input
.AP int addAtEnd in
Flag indicating whether the input should be added to the end or
beginning of the channel buffer.
-.VE
.AP Tcl_Obj *writeObjPtr in
-A pointer to a Tcl Object whose contents will be output to the channel.
-.AP "CONST char" *charBuf in
+A pointer to a Tcl value whose contents will be output to the channel.
+.AP "const char" *charBuf in
A buffer containing the characters to output to the channel.
-.AP "CONST char" *byteBuf in
+.AP "const char" *byteBuf in
A buffer containing the bytes to output to the channel.
.AP int bytesToWrite in
The number of bytes to consume from \fIcharBuf\fR or \fIbyteBuf\fR and
output to the channel.
-.VE
-.AP int offset in
+.AP Tcl_WideInt offset in
How far to move the access point in the channel at which the next input or
output operation will be applied, measured in bytes from the position
given by \fIseekMode\fR. May be either positive or negative.
Relative to which point to seek; used with \fIoffset\fR to calculate the new
access point for the channel. Legal values are \fBSEEK_SET\fR,
\fBSEEK_CUR\fR, and \fBSEEK_END\fR.
-.AP "CONST char" *optionName in
+.AP Tcl_WideInt length in
+The (non-negative) length to truncate the channel the channel to.
+.AP "const char" *optionName in
The name of an option applicable to this channel, such as \fB\-blocking\fR.
May have any of the values accepted by the \fBfconfigure\fR command.
.AP Tcl_DString *optionValue in
Where to store the value of an option or a list of all options and their
values. Must have been initialized by the caller.
-.AP "CONST char" *newValue in
+.AP "const char" *newValue in
New value for the option given by \fIoptionName\fR.
.BE
-
.SH DESCRIPTION
.PP
The Tcl channel mechanism provides a device-independent and
and output operations on a variety of file, socket, and device
types.
The channel mechanism is extensible to new channel types, by
-providing a low level channel driver for the new type; the channel driver
+providing a low-level channel driver for the new type; the channel driver
interface is described in the manual entry for \fBTcl_CreateChannel\fR. The
channel mechanism provides a buffering scheme modeled after
Unix's standard I/O, and it also allows for nonblocking I/O on
generic layer of the channel architecture. For a description of the channel
driver architecture and how to implement channel drivers for new types of
channels, see the manual entry for \fBTcl_CreateChannel\fR.
-
.SH TCL_OPENFILECHANNEL
.PP
\fBTcl_OpenFileChannel\fR opens a file specified by \fIfileName\fR and
retrieved with \fBTcl_GetErrno\fR.
In addition, if \fIinterp\fR is non-NULL, \fBTcl_OpenFileChannel\fR
leaves an error message in \fIinterp\fR's result after any error.
-As of Tcl 8.4, the object-based API \fBTcl_FSOpenFileChannel\fR should
+As of Tcl 8.4, the value-based API \fBTcl_FSOpenFileChannel\fR should
be used in preference to \fBTcl_OpenFileChannel\fR wherever possible.
.PP
-
-.PP
The newly created channel is not registered in the supplied interpreter; to
register it, use \fBTcl_RegisterChannel\fR, described below.
-If one of the standard channels, \fBstdin, stdout\fR or \fBstderr\fR was
+If one of the standard channels, \fBstdin\fR, \fBstdout\fR or \fBstderr\fR was
previously closed, the act of creating the new channel also assigns it as a
replacement for the standard channel.
-
.SH TCL_OPENCOMMANDCHANNEL
.PP
\fBTcl_OpenCommandChannel\fR provides a C-level interface to the
.PP
The newly created channel is not registered in the supplied interpreter; to
register it, use \fBTcl_RegisterChannel\fR, described below.
-If one of the standard channels, \fBstdin, stdout\fR or \fBstderr\fR was
+If one of the standard channels, \fBstdin\fR, \fBstdout\fR or \fBstderr\fR was
previously closed, the act of creating the new channel also assigns it as a
replacement for the standard channel.
-
.SH TCL_MAKEFILECHANNEL
.PP
\fBTcl_MakeFileChannel\fR makes a \fBTcl_Channel\fR from an existing,
platform-specific, file handle.
The newly created channel is not registered in the supplied interpreter; to
register it, use \fBTcl_RegisterChannel\fR, described below.
-If one of the standard channels, \fBstdin, stdout\fR or \fBstderr\fR was
+If one of the standard channels, \fBstdin\fR, \fBstdout\fR or \fBstderr\fR was
previously closed, the act of creating the new channel also assigns it as a
replacement for the standard channel.
-
.SH TCL_GETCHANNEL
.PP
\fBTcl_GetChannel\fR returns a channel given the \fIchannelName\fR used to
.PP
\fBTcl_GetChannelNames\fR and \fBTcl_GetChannelNamesEx\fR write the
names of the registered channels to the interpreter's result as a
-list object. \fBTcl_GetChannelNamesEx\fR will filter these names
+list value. \fBTcl_GetChannelNamesEx\fR will filter these names
according to the \fIpattern\fR. If \fIpattern\fR is NULL, then it
will not do any filtering. The return value is \fBTCL_OK\fR if no
errors occurred writing to the result, otherwise it is \fBTCL_ERROR\fR,
and the error message is left in the interpreter's result.
-
.SH TCL_REGISTERCHANNEL
.PP
\fBTcl_RegisterChannel\fR adds a channel to the set of channels accessible
.PP
This procedure interacts with the code managing the standard
channels. If no standard channels were initialized before the first
-call to \fBTcl_RegisterChannel\fR they will get initialized by that
+call to \fBTcl_RegisterChannel\fR, they will get initialized by that
call. See \fBTcl_StandardChannels\fR for a general treatise about
-standard channels and the behaviour of the Tcl library with regard to
+standard channels and the behavior of the Tcl library with regard to
them.
-
.SH TCL_UNREGISTERCHANNEL
.PP
\fBTcl_UnregisterChannel\fR removes a channel from the set of channels
reference to the channel, it will now be closed. \fBTcl_UnregisterChannel\fR
is very similar to \fBTcl_DetachChannel\fR except that it will also
close the channel if no further references to it exist.
-
.SH TCL_DETACHCHANNEL
.PP
\fBTcl_DetachChannel\fR removes a channel from the set of channels
accessible in \fIinterp\fR. After this call, Tcl programs will no longer be
able to use the channel's name to refer to the channel in that interpreter.
Beyond that, this command has no further effect. It cannot be used on
-the standard channels (stdout, stderr, stdin), and will return
-TCL_ERROR if passed one of those channels.
+the standard channels (\fBstdout\fR, \fBstderr\fR, \fBstdin\fR), and will return
+\fBTCL_ERROR\fR if passed one of those channels.
.PP
Code not associated with a Tcl interpreter can call
\fBTcl_DetachChannel\fR with \fIinterp\fR as NULL, to indicate to Tcl
that it no longer holds a reference to that channel. If this is the last
reference to the channel, unlike \fBTcl_UnregisterChannel\fR,
it will not be closed.
-
.SH TCL_ISSTANDARDCHANNEL
.PP
\fBTcl_IsStandardChannel\fR tests whether a channel is one of the
-three standard channels, stdin, stdout or stderr. If so, it returns
-1, otherwise 0.
+three standard channels, \fBstdin\fR, \fBstdout\fR or \fBstderr\fR.
+If so, it returns 1, otherwise 0.
.PP
No attempt is made to check whether the given channel or the standard
channels are initialized or otherwise valid.
-
.SH TCL_CLOSE
.PP
\fBTcl_Close\fR destroys the channel \fIchannel\fR, which must denote a
\fBTcl_UnregisterChannel\fR, which will internally call \fBTcl_Close\fR
when all calls to \fBTcl_RegisterChannel\fR have been matched by
corresponding calls to \fBTcl_UnregisterChannel\fR.
-
-.VS 8.1 br
.SH "TCL_READCHARS AND TCL_READ"
.PP
\fBTcl_ReadChars\fR consumes bytes from \fIchannel\fR, converting the bytes
return value is \-1 and \fBTcl_ReadChars\fR records a POSIX error code that
can be retrieved with \fBTcl_GetErrno\fR.
.PP
+Setting \fIcharsToRead\fR to \fB\-1\fR will cause the command to read
+all characters currently available (non-blocking) or everything until
+eof (blocking mode).
+.PP
The return value may be smaller than the value to read, indicating that less
data than requested was available. This is called a \fIshort read\fR. In
blocking mode, this can only happen on an end-of-file. In nonblocking mode,
As a performance optimization, when reading from a channel with the encoding
\fBbinary\fR, the bytes are not converted to UTF-8 as they are read.
Instead, they are stored in \fIreadObjPtr\fR's internal representation as a
-byte-array object. The string representation of this object will only be
+byte-array value. The string representation of this value will only be
constructed if it is needed (e.g., because of a call to
\fBTcl_GetStringFromObj\fR). In this way, byte-oriented data can be read
from a channel, manipulated by calling \fBTcl_GetByteArrayFromObj\fR and
related functions, and then written to a channel without the expense of ever
converting to or from UTF-8.
.PP
-\fBTcl_Read\fR is similar to \fBTcl_ReadChars\fR, except that it doesn't do
+\fBTcl_Read\fR is similar to \fBTcl_ReadChars\fR, except that it does not do
encoding conversions, regardless of the channel's encoding. It is deprecated
and exists for backwards compatibility with non-internationalized Tcl
extensions. It consumes bytes from \fIchannel\fR and stores them in
not. Thus this function is \fBonly\fR usable for transformational
channel drivers, i.e. drivers used in the middle of a stack of
channels, to move data from the channel below into the transformation.
-
.SH "TCL_GETSOBJ AND TCL_GETS"
.PP
\fBTcl_GetsObj\fR consumes bytes from \fIchannel\fR, converting the bytes to
.PP
\fBTcl_Gets\fR is the same as \fBTcl_GetsObj\fR except the resulting
characters are appended to the dynamic string given by
-\fIlineRead\fR rather than a Tcl object.
-
+\fIlineRead\fR rather than a Tcl value.
.SH "TCL_UNGETS"
.PP
\fBTcl_Ungets\fR is used to add data to the input queue of a channel,
to the data that is to be added. The length of the input to add is given
by \fIinputLen\fR. A non-zero value of \fIaddAtEnd\fR indicates that the
data is to be added at the end of queue; otherwise it will be added at the
-head of the queue. If \fIchannel\fR has a "sticky" EOF set, no data will be
+head of the queue. If \fIchannel\fR has a
+.QW sticky
+EOF set, no data will be
added to the input queue. \fBTcl_Ungets\fR returns \fIinputLen\fR or
--1 if an error occurs.
-
+\-1 if an error occurs.
.SH "TCL_WRITECHARS, TCL_WRITEOBJ, AND TCL_WRITE"
.PP
\fBTcl_WriteChars\fR accepts \fIbytesToWrite\fR bytes of character data at
channel. This is done even if the channel has no encoding.
.PP
\fBTcl_WriteObj\fR is similar to \fBTcl_WriteChars\fR except it
-accepts a Tcl object whose contents will be output to the channel. The
+accepts a Tcl value whose contents will be output to the channel. The
UTF-8 characters in \fIwriteObjPtr\fR's string representation are converted
to the channel's encoding and queued for output to \fIchannel\fR.
As a performance optimization, when writing to a channel with the encoding
\fBbinary\fR, UTF-8 characters are not converted as they are written.
Instead, the bytes in \fIwriteObjPtr\fR's internal representation as a
-byte-array object are written to the channel. The byte-array representation
-of the object will be constructed if it is needed. In this way,
+byte-array value are written to the channel. The byte-array representation
+of the value will be constructed if it is needed. In this way,
byte-oriented data can be read from a channel, manipulated by calling
\fBTcl_GetByteArrayFromObj\fR and related functions, and then written to a
channel without the expense of ever converting to or from UTF-8.
.PP
-\fBTcl_Write\fR is similar to \fBTcl_WriteChars\fR except that it doesn't do
+\fBTcl_Write\fR is similar to \fBTcl_WriteChars\fR except that it does not do
encoding conversions, regardless of the channel's encoding. It is
deprecated and exists for backwards compatibility with non-internationalized
Tcl extensions. It accepts \fIbytesToWrite\fR bytes of data at
channel drivers, i.e. drivers used in the middle of a stack of
channels, to move data from the transformation into the channel below
it.
-.VE
-
.SH TCL_FLUSH
.PP
\fBTcl_Flush\fR causes all of the buffered output data for \fIchannel\fR
The return value is normally \fBTCL_OK\fR.
If an error occurs, \fBTcl_Flush\fR returns \fBTCL_ERROR\fR and
records a POSIX error code that can be retrieved with \fBTcl_GetErrno\fR.
-
.SH TCL_SEEK
.PP
\fBTcl_Seek\fR moves the access point in \fIchannel\fR where subsequent
If an error occurs, \fBTcl_Seek\fR returns \-1 and records a POSIX error
code that can be retrieved with \fBTcl_GetErrno\fR.
After an error, the access point may or may not have been moved.
-
.SH TCL_TELL
.PP
\fBTcl_Tell\fR returns the current access point for a channel. The returned
value is \-1 if the channel does not support seeking.
-
+.SH TCL_TRUNCATECHANNEL
+.PP
+\fBTcl_TruncateChannel\fR truncates the file underlying \fIchannel\fR
+to a given \fIlength\fR of bytes. It returns \fBTCL_OK\fR if the
+operation succeeded, and \fBTCL_ERROR\fR otherwise.
.SH TCL_GETCHANNELOPTION
.PP
\fBTcl_GetChannelOption\fR retrieves, in \fIoptionValue\fR, the value of one of
The procedure normally returns \fBTCL_OK\fR. If an error occurs, it returns
\fBTCL_ERROR\fR and calls \fBTcl_SetErrno\fR to store an appropriate POSIX
error code.
-
.SH TCL_SETCHANNELOPTION
.PP
\fBTcl_SetChannelOption\fR sets a new value \fInewValue\fR
The procedure normally returns \fBTCL_OK\fR. If an error occurs,
it returns \fBTCL_ERROR\fR; in addition, if \fIinterp\fR is non-NULL,
\fBTcl_SetChannelOption\fR leaves an error message in the interpreter's result.
-
.SH TCL_EOF
.PP
\fBTcl_Eof\fR returns a nonzero value if \fIchannel\fR encountered
an end of file during the last input operation.
-
.SH TCL_INPUTBLOCKED
.PP
\fBTcl_InputBlocked\fR returns a nonzero value if \fIchannel\fR is in
nonblocking mode and the last input operation returned less data than
requested because there was insufficient data available.
The call always returns zero if the channel is in blocking mode.
-
.SH TCL_INPUTBUFFERED
.PP
\fBTcl_InputBuffered\fR returns the number of bytes of input currently
buffered in the internal buffers for a channel. If the channel is not open
for reading, this function always returns zero.
-
.SH TCL_OUTPUTBUFFERED
-.VS 8.4
+.PP
\fBTcl_OutputBuffered\fR returns the number of bytes of output
currently buffered in the internal buffers for a channel. If the
channel is not open for writing, this function always returns zero.
-.VE
-
.SH "PLATFORM ISSUES"
.PP
The handles returned from \fBTcl_GetChannelHandle\fR depend on the
the channel was created with \fBTcl_OpenFileChannel\fR,
\fBTcl_OpenCommandChannel\fR, or \fBTcl_MakeFileChannel\fR. Other
channel types may return a different type of handle on Windows
-platforms. On the Macintosh platform, the handle is a file reference
-number as returned from \fBHOpenDF\fR.
-
+platforms.
.SH "SEE ALSO"
DString(3), fconfigure(n), filename(n), fopen(3), Tcl_CreateChannel(3)
-
.SH KEYWORDS
access point, blocking, buffered I/O, channel, channel driver, end of file,
flush, input, nonblocking, output, read, seek, write
OSDN Git Service
