crtchannel.3

tcl是工具命令语言

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'\" RCS: @(#) $Id: CrtChannel.3,v 1.16 2002/07/01 18:24:39 jenglish Exp $
.so man.macros
.TH Tcl_CreateChannel 3 8.3 Tcl "Tcl Library Procedures"
.BS
'\" Note:  do not modify the .SH NAME line immediately below!
.SH NAME
Tcl_CreateChannel, Tcl_GetChannelInstanceData, Tcl_GetChannelType, Tcl_GetChannelName, Tcl_GetChannelHandle, Tcl_GetChannelMode, Tcl_GetChannelBufferSize, Tcl_SetChannelBufferSize, Tcl_NotifyChannel, Tcl_BadChannelOption, Tcl_ChannelName, Tcl_ChannelVersion, Tcl_ChannelBlockModeProc, Tcl_ChannelCloseProc, Tcl_ChannelClose2Proc, Tcl_ChannelInputProc, Tcl_ChannelOutputProc, Tcl_ChannelSeekProc, Tcl_ChannelWideSeekProc, Tcl_ChannelSetOptionProc, Tcl_ChannelGetOptionProc, Tcl_ChannelWatchProc, Tcl_ChannelGetHandleProc, Tcl_ChannelFlushProc, Tcl_ChannelHandlerProc, Tcl_IsChannelShared, Tcl_IsChannelRegistered, Tcl_CutChannel, Tcl_SpliceChannel, Tcl_IsChannelExisting, Tcl_ClearChannelHandlers, Tcl_GetChannelThread, Tcl_ChannelBuffered \- procedures for creating and manipulating channels
.SH SYNOPSIS
.nf
\fB#include <tcl.h>\fR
.sp
Tcl_Channel
\fBTcl_CreateChannel\fR(\fItypePtr, channelName, instanceData, mask\fR)
.sp
ClientData
\fBTcl_GetChannelInstanceData\fR(\fIchannel\fR)
.sp
Tcl_ChannelType *
\fBTcl_GetChannelType\fR(\fIchannel\fR)
.sp
CONST char *
\fBTcl_GetChannelName\fR(\fIchannel\fR)
.sp
int
\fBTcl_GetChannelHandle\fR(\fIchannel, direction, handlePtr\fR)
.sp
.VS 8.4
Tcl_ThreadId
\fBTcl_GetChannelThread\fR(\fIchannel\fR)
.VE 8.4
.sp
int
\fBTcl_GetChannelBufferSize\fR(\fIchannel\fR)
.sp
\fBTcl_SetChannelBufferSize\fR(\fIchannel, size\fR)
.sp
\fBTcl_NotifyChannel\fR(\fIchannel, mask\fR)
.sp
int
\fBTcl_BadChannelOption\fR(\fIinterp, optionName, optionList\fR)
.VS 8.4
.sp
int
\fBTcl_IsChannelShared\fR(\fIchannel\fR)
.sp
int
\fBTcl_IsChannelRegistered\fR(\fIinterp, channel\fR)
.sp
int
\fBTcl_IsChannelExisting\fR(\fIchannelName\fR)
.sp
void
\fBTcl_CutChannel\fR(\fIchannel\fR)
.sp
void
\fBTcl_SpliceChannel\fR(\fIchannel\fR)
.sp
void
\fBTcl_ClearChannelHandlers\fR(\fIchannel\fR)
.VE 8.4
.sp
int
\fBTcl_ChannelBuffered\fR(\fIchannel\fR)
.sp
CONST char *
\fBTcl_ChannelName\fR(\fItypePtr\fR)
.sp
Tcl_ChannelTypeVersion
\fBTcl_ChannelVersion\fR(\fItypePtr\fR)
.sp
Tcl_DriverBlockModeProc *
\fBTcl_ChannelBlockModeProc\fR(\fItypePtr\fR)
.sp
Tcl_DriverCloseProc *
\fBTcl_ChannelCloseProc\fR(\fItypePtr\fR)
.sp
Tcl_DriverClose2Proc *
\fBTcl_ChannelClose2Proc\fR(\fItypePtr\fR)
.sp
Tcl_DriverInputProc *
\fBTcl_ChannelInputProc\fR(\fItypePtr\fR)
.sp
Tcl_DriverOutputProc *
\fBTcl_ChannelOutputProc\fR(\fItypePtr\fR)
.sp
Tcl_DriverSeekProc *
\fBTcl_ChannelSeekProc\fR(\fItypePtr\fR)
.sp
.VS 8.4
Tcl_DriverWideSeekProc *
\fBTcl_ChannelWideSeekProc\fR(\fItypePtr\fR)
.VE 8.4
.sp
Tcl_DriverSetOptionProc *
\fBTcl_ChannelSetOptionProc\fR(\fItypePtr\fR)
.sp
Tcl_DriverGetOptionProc *
\fBTcl_ChannelGetOptionProc\fR(\fItypePtr\fR)
.sp
Tcl_DriverWatchProc *
\fBTcl_ChannelWatchProc\fR(\fItypePtr\fR)
.sp
Tcl_DriverGetHandleProc *
\fBTcl_ChannelGetHandleProc\fR(\fItypePtr\fR)
.sp
Tcl_DriverFlushProc *
\fBTcl_ChannelFlushProc\fR(\fItypePtr\fR)
.sp
Tcl_DriverHandlerProc *
\fBTcl_ChannelHandlerProc\fR(\fItypePtr\fR)
.sp
.SH ARGUMENTS
.AS Tcl_ChannelType *channelName in
.AP Tcl_ChannelType *typePtr in
Points to a structure containing the addresses of procedures that
can be called to perform I/O and other functions on the channel.
.AP "CONST char" *channelName in
The name of this channel, such as \fBfile3\fR; must not be in use
by any other channel. Can be NULL, in which case the channel is
created without a name.
.AP ClientData instanceData in
Arbitrary one-word value to be associated with this channel.  This
value is passed to procedures in \fItypePtr\fR when they are invoked.
.AP int mask in
OR-ed combination of \fBTCL_READABLE\fR and \fBTCL_WRITABLE\fR to indicate
whether a channel is readable and writable.
.AP Tcl_Channel channel in
The channel to operate on.
.AP int direction in
\fBTCL_READABLE\fR means the input handle is wanted; \fBTCL_WRITABLE\fR
means the output handle is wanted.
.AP ClientData *handlePtr out
Points to the location where the desired OS-specific handle should be
stored.
.AP int size in
The size, in bytes, of buffers to allocate in this channel.
.AP int mask in
An OR-ed combination of \fBTCL_READABLE\fR, \fBTCL_WRITABLE\fR
and \fBTCL_EXCEPTION\fR that indicates events that have occurred on
this channel.
.AP Tcl_Interp *interp in
Current interpreter. (can be NULL)
.AP "CONST char" *optionName in
Name of the invalid option.
.AP "CONST char" *optionList in
Specific options list (space separated words, without "-") 
to append to the standard generic options list.
Can be NULL for generic options error message only.

.BE

.SH DESCRIPTION
.PP
Tcl uses a two-layered channel architecture. It provides a generic upper
layer to enable C and Tcl programs to perform input and output using the
same APIs for a variety of files, devices, sockets etc. The generic C APIs
are described in the manual entry for \fBTcl_OpenFileChannel\fR.
.PP
The lower layer provides type-specific channel drivers for each type
of device supported on each platform.  This manual entry describes the
C APIs used to communicate between the generic layer and the
type-specific channel drivers.  It also explains how new types of
channels can be added by providing new channel drivers.
.PP
Channel drivers consist of a number of components: First, each channel
driver provides a \fBTcl_ChannelType\fR structure containing pointers to
functions implementing the various operations used by the generic layer to
communicate with the channel driver. The \fBTcl_ChannelType\fR structure
and the functions referenced by it are described in the section
TCL_CHANNELTYPE, below.
.PP
Second, channel drivers usually provide a Tcl command to create
instances of that type of channel. For example, the Tcl \fBopen\fR
command creates channels that use the file and command channel
drivers, and the Tcl \fBsocket\fR command creates channels that use
TCP sockets for network communication.
.PP
Third, a channel driver optionally provides a C function to open
channel instances of that type. For example, \fBTcl_OpenFileChannel\fR
opens a channel that uses the file channel driver, and
\fBTcl_OpenTcpClient\fR opens a channel that uses the TCP network
protocol.  These creation functions typically use
\fBTcl_CreateChannel\fR internally to open the channel.
.PP
To add a new type of channel you must implement a C API or a Tcl command
that opens a channel by invoking \fBTcl_CreateChannel\fR.
When your driver calls \fBTcl_CreateChannel\fR it passes in
a \fBTcl_ChannelType\fR structure describing the driver's I/O
procedures.
The generic layer will then invoke the functions referenced in that
structure to perform operations on the channel.
.PP
\fBTcl_CreateChannel\fR opens a new channel and associates the supplied
\fItypePtr\fR and \fIinstanceData\fR with it. The channel is opened in the
mode indicated by \fImask\fR.
For a discussion of channel drivers, their operations and the
\fBTcl_ChannelType\fR structure, see the section TCL_CHANNELTYPE, below.
.PP
\fBTcl_CreateChannel\fR interacts with the code managing the standard
channels. Once a standard channel was initialized either through a
call to \fBTcl_GetStdChannel\fR or a call to \fBTcl_SetStdChannel\fR
closing this standard channel will cause the next call to
\fBTcl_CreateChannel\fR to make the new channel the new standard
channel too. See \fBTcl_StandardChannels\fR for a general treatise
about standard channels and the behaviour of the Tcl library with
regard to them.
.PP
\fBTcl_GetChannelInstanceData\fR returns the instance data associated with
the channel in \fIchannel\fR. This is the same as the \fIinstanceData\fR
argument in the call to \fBTcl_CreateChannel\fR that created this channel.
.PP
\fBTcl_GetChannelType\fR returns a pointer to the \fBTcl_ChannelType\fR
structure used by the channel in the \fIchannel\fR argument. This is
the same as the \fItypePtr\fR argument in the call to
\fBTcl_CreateChannel\fR that created this channel.
.PP
\fBTcl_GetChannelName\fR returns a string containing the name associated
with the channel, or NULL if the \fIchannelName\fR argument to
\fBTcl_CreateChannel\fR was NULL.
.PP
\fBTcl_GetChannelHandle\fR places the OS-specific device handle
associated with \fIchannel\fR for the given \fIdirection\fR in the
location specified by \fIhandlePtr\fR and returns \fBTCL_OK\fR.  If
the channel does not have a device handle for the specified direction,
then \fBTCL_ERROR\fR is returned instead.  Different channel drivers
will return different types of handle.  Refer to the manual entries
for each driver to determine what type of handle is returned.
.VS 8.4
.PP
\fBTcl_GetChannelThread\fR returns the id of the thread currently managing
the specified \fIchannel\fR. This allows channel drivers to send their file
events to the correct event queue even for a multi-threaded core.
.VE 8.4
.PP
\fBTcl_GetChannelMode\fR returns an OR-ed combination of \fBTCL_READABLE\fR
and \fBTCL_WRITABLE\fR, indicating whether the channel is open for input
and output.
.PP
\fBTcl_GetChannelBufferSize\fR returns the size, in bytes, of buffers
allocated to store input or output in \fIchannel\fR. If the value was not set
by a previous call to \fBTcl_SetChannelBufferSize\fR, described below, then
the default value of 4096 is returned.
.PP
\fBTcl_SetChannelBufferSize\fR sets the size, in bytes, of buffers that
will be allocated in subsequent operations on the channel to store input or
output. The \fIsize\fR argument should be between ten and one million,
allowing buffers of ten bytes to one million bytes. If \fIsize\fR is
outside this range, \fBTcl_SetChannelBufferSize\fR sets the buffer size to
4096.
.PP
\fBTcl_NotifyChannel\fR is called by a channel driver to indicate to
the generic layer that the events specified by \fImask\fR have
occurred on the channel.  Channel drivers are responsible for invoking
this function whenever the channel handlers need to be called for the
channel.  See \fBWATCHPROC\fR below for more details.
.PP
\fBTcl_BadChannelOption\fR is called from driver specific set or get option
procs to generate a complete error message.
.PP
\fBTcl_ChannelBuffered\fR returns the number of bytes of input
currently buffered in the internal buffer (push back area) of the
channel itself. It does not report about the data in the overall
buffers for the stack of channels the supplied channel is part of.
.PP
.VS 8.4
\fBTcl_IsChannelShared\fR checks the refcount of the specified
\fIchannel\fR and returns whether the \fIchannel\fR was shared among
multiple interpreters (result == 1) or not (result == 0).
.PP
\fBTcl_IsChannelRegistered\fR checks whether the specified \fIchannel\fR is
registered in the given \fIinterp\fRreter (result == 1) or not
(result == 0).
.PP
\fBTcl_IsChannelExisting\fR checks whether a channel with the specified
name is registered in the (thread)-global list of all channels (result
== 1) or not (result == 0).
.PP
\fBTcl_CutChannel\fR removes the specified \fIchannel\fR from the
(thread)global list of all channels (of the current thread).
Application to a channel still registered in some interpreter
is not allowed.
.PP
\fBTcl_SpliceChannel\fR adds the specified \fIchannel\fR to the