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Diffstat (limited to 'doc/OpenFileChnl.3')
| -rw-r--r-- | doc/OpenFileChnl.3 | 270 |
1 files changed, 166 insertions, 104 deletions
diff --git a/doc/OpenFileChnl.3 b/doc/OpenFileChnl.3 index d0d751a..cca76c2 100644 --- a/doc/OpenFileChnl.3 +++ b/doc/OpenFileChnl.3 @@ -4,40 +4,33 @@ '\" 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 1.7 1999/08/21 19:40:47 hobbs Exp $ -.so man.macros .TH Tcl_OpenFileChannel 3 8.3 Tcl "Tcl Library Procedures" +.so man.macros .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_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 \- 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 -typedef ... Tcl_Channel; -.sp Tcl_Channel \fBTcl_OpenFileChannel\fR(\fIinterp, fileName, mode, permissions\fR) .sp Tcl_Channel \fBTcl_OpenCommandChannel\fR(\fIinterp, argc, argv, flags\fR) -.VS 8.0 .sp Tcl_Channel \fBTcl_MakeFileChannel\fR(\fIhandle, readOrWrite\fR) -.VE .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) @@ -46,14 +39,19 @@ int \fBTcl_UnregisterChannel\fR(\fIinterp, channel\fR) .sp int +\fBTcl_DetachChannel\fR(\fIinterp, channel\fR) +.sp +int +\fBTcl_IsStandardChannel\fR(\fIchannel\fR) +.sp +int \fBTcl_Close\fR(\fIinterp, channel\fR) .sp -.VS 8.1 int \fBTcl_ReadChars\fR(\fIchannel, readObjPtr, charsToRead, appendFlag\fR) .sp int -\fBTcl_Read\fR(\fIchannel, byteBuf, bytesToRead\fR) +\fBTcl_Read\fR(\fIchannel, readBuf, bytesToRead\fR) .sp int \fBTcl_GetsObj\fR(\fIchannel, lineObjPtr\fR) @@ -62,6 +60,9 @@ int \fBTcl_Gets\fR(\fIchannel, lineRead\fR) .sp int +\fBTcl_Ungets\fR(\fIchannel, input, inputLen, addAtEnd\fR) +.sp +int \fBTcl_WriteObj\fR(\fIchannel, writeObjPtr\fR) .sp int @@ -69,48 +70,58 @@ int .sp int \fBTcl_Write\fR(\fIchannel, byteBuf, bytesToWrite\fR) -.VE .sp int -\fBTcl_Flush\fR(\fIchannel\fR) +\fBTcl_ReadRaw\fR(\fIchannel, readBuf, bytesToRead\fR) .sp int -\fBTcl_Seek\fR(\fIchannel, offset, seekMode\fR) +\fBTcl_WriteRaw\fR(\fIchannel, byteBuf, bytesToWrite\fR) .sp int -\fBTcl_Tell\fR(\fIchannel\fR) +\fBTcl_Eof\fR(\fIchannel\fR) .sp int -\fBTcl_GetChannelOption\fR(\fIinterp, channel, optionName, optionValue\fR) +\fBTcl_Flush\fR(\fIchannel\fR) .sp int -\fBTcl_SetChannelOption\fR(\fIinterp, channel, optionName, newValue\fR) +\fBTcl_InputBlocked\fR(\fIchannel\fR) .sp int -\fBTcl_Eof\fR(\fIchannel\fR) +\fBTcl_InputBuffered\fR(\fIchannel\fR) .sp int -\fBTcl_InputBlocked\fR(\fIchannel\fR) +\fBTcl_OutputBuffered\fR(\fIchannel\fR) +.sp +Tcl_WideInt +\fBTcl_Seek\fR(\fIchannel, offset, seekMode\fR) +.sp +Tcl_WideInt +\fBTcl_Tell\fR(\fIchannel\fR) .sp int -\fBTcl_InputBuffered\fR(\fIchannel\fR) +\fBTcl_TruncateChannel\fR(\fIchannel, length\fR) +.sp +int +\fBTcl_GetChannelOption\fR(\fIinterp, channel, optionName, optionValue\fR) +.sp +int +\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 char *fileName in +.AP "const char" *fileName in The name of a local or network file. -.AP 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. For -\fBTcl_OpenCommandChannel\fR, may be NULL. +allowed for the \fImode\fR argument to the Tcl \fBopen\fR command. .AP int permissions in POSIX-style permission flags such as 0644. If a new file is created, these permissions will be set on the created file. .AP int argc in The number of elements in \fIargv\fR. -.AP 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 @@ -123,58 +134,63 @@ input of the invoking process; likewise for \fBTCL_STDOUT\fR and redirect stdio handles to override the stdio handles for which \fBTCL_STDIN\fR, \fBTCL_STDOUT\fR and \fBTCL_STDERR\fR have been set. If it is set, then such redirections cause an error. -.VS 8.0 .AP ClientData handle in Operating system specific handle for I/O to a file. For Unix this is a file descriptor, for Windows it is a HANDLE. .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 char *channelName in +.AP "const char" *channelName in The name of the channel. -.VE .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. +.AP "const char" *pattern in +The pattern to match on, passed to Tcl_StringMatch, or NULL. .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. +.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. .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 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. @@ -182,20 +198,17 @@ 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 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 char *newValue in +.AP "const char" *newValue in New value for the option given by \fIoptionName\fR. -.VS 8.3 -.AP char *pattern in -The pattern to match on, passed to Tcl_StringMatch, or NULL. -.VE .BE - .SH DESCRIPTION .PP The Tcl channel mechanism provides a device-independent and @@ -203,7 +216,7 @@ platform-independent mechanism for performing buffered input 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 @@ -213,7 +226,6 @@ The procedures described in this manual entry comprise the C APIs of the 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 @@ -226,14 +238,15 @@ If an error occurs while opening the channel, \fBTcl_OpenFileChannel\fR returns NULL and records a POSIX error code that can be 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. +leaves an error message in \fIinterp\fR's result after any error. +As of Tcl 8.4, the value-based API \fBTcl_FSOpenFileChannel\fR should +be used in preference to \fBTcl_OpenFileChannel\fR wherever possible. .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 @@ -264,42 +277,39 @@ If an error occurs while opening the channel, \fBTcl_OpenCommandChannel\fR returns NULL and records a POSIX error code that can be retrieved with \fBTcl_GetErrno\fR. In addition, \fBTcl_OpenCommandChannel\fR leaves an error message in -\fIinterp->result\fR if \fIinterp\fR is not NULL. +the interpreter's result if \fIinterp\fR is not NULL. .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 create it with \fBTcl_CreateChannel\fR and a pointer to a Tcl interpreter in \fIinterp\fR. If a channel by that name is not registered in that interpreter, -the procedure returns NULL. If the \fImode\fR argument is not NULL, it +the procedure returns NULL. If the \fImodePtr\fR argument is not NULL, it points at an integer variable that will receive an OR-ed combination of \fBTCL_READABLE\fR and \fBTCL_WRITABLE\fR describing whether the channel is open for reading and writing. .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 occured writing to the result, otherwise it is \fBTCL_ERROR\fR, +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 @@ -317,7 +327,13 @@ be registered in a Tcl interpreter and it will only be closed when the matching number of calls to \fBTcl_UnregisterChannel\fR have been made. This allows code executing outside of any interpreter to safely hold a reference to a channel that is also registered in a Tcl interpreter. - +.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. See \fBTcl_StandardChannels\fR for a general treatise about +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 @@ -329,8 +345,31 @@ interpreter, the channel is also closed and destroyed. Code not associated with a Tcl interpreter can call \fBTcl_UnregisterChannel\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, it will now be closed. - +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 (\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, \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 @@ -360,18 +399,20 @@ been given as the \fBchan\fR argument in a call to \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 to UTF-8 based on the channel's encoding and storing the produced data in \fIreadObjPtr\fR's string representation. The return value of \fBTcl_ReadChars\fR is the number of characters, up to \fIcharsToRead\fR, -that were stored in \fIobjPtr\fR. If an error occurs while reading, the +that were stored in \fIreadObjPtr\fR. If an error occurs while reading, the 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, @@ -394,23 +435,30 @@ platform-specific modes are described in the manual entry for the Tcl 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 -\fIbuf\fR, performing end-of-line translations on the way. The return value -of \fBTcl_Read\fR is the number of bytes, up to \fItoRead\fR, written in -\fIbuf\fR. The buffer produced by \fBTcl_Read\fR is not NULL terminated. +\fIreadBuf\fR, performing end-of-line translations on the way. The return value +of \fBTcl_Read\fR is the number of bytes, up to \fIbytesToRead\fR, written in +\fIreadBuf\fR. The buffer produced by \fBTcl_Read\fR is not null-terminated. Its contents are valid from the zeroth position up to and excluding the position indicated by the return value. - +.PP +\fBTcl_ReadRaw\fR is the same as \fBTcl_Read\fR but does not +compensate for stacking. While \fBTcl_Read\fR (and the other functions +in the API) always get their data from the topmost channel in the +stack the supplied channel is part of, \fBTcl_ReadRaw\fR does +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 @@ -435,16 +483,27 @@ procedure may be invoked to determine if the channel is blocked because of input unavailability. .PP \fBTcl_Gets\fR is the same as \fBTcl_GetsObj\fR except the resulting -characters are appended to the appended to the dynamic string given by -\fIdsPtr\fR rather than a Tcl object. - +characters are appended to the dynamic string given by +\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, +at either the head or tail of the queue. The pointer \fIinput\fR points +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 +.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. .SH "TCL_WRITECHARS, TCL_WRITEOBJ, AND TCL_WRITE" .PP \fBTcl_WriteChars\fR accepts \fIbytesToWrite\fR bytes of character data at \fIcharBuf\fR. The UTF-8 characters in the buffer are converted to the channel's encoding and queued for output to \fIchannel\fR. If \fIbytesToWrite\fR is negative, \fBTcl_WriteChars\fR expects \fIcharBuf\fR -to be NULL terminated and it outputs everything up to the NULL. +to be null-terminated and it outputs everything up to the null. .PP Data queued for output may not appear on the output device immediately, due to internal buffering. If the data should appear immediately, call @@ -464,27 +523,34 @@ end-of-line sequences according to the \fB\-translation\fR option for the 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 \fIbyteBuf\fR and queues them for output to \fIchannel\fR. If \fIbytesToWrite\fR is negative, \fBTcl_Write\fR expects \fIbyteBuf\fR to be -NULL terminated and it outputs everything up to the NULL. -.VE - +null-terminated and it outputs everything up to the null. +.PP +\fBTcl_WriteRaw\fR is the same as \fBTcl_Write\fR but does not +compensate for stacking. While \fBTcl_Write\fR (and the other +functions in the API) always feed their input to the topmost channel +in the stack the supplied channel is part of, \fBTcl_WriteRaw\fR does +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 transformation into the channel below +it. .SH TCL_FLUSH .PP \fBTcl_Flush\fR causes all of the buffered output data for \fIchannel\fR @@ -498,7 +564,6 @@ eventually, as fast as the channel is able to absorb it. 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 @@ -509,15 +574,18 @@ buffered input is discarded, prior to the seek operation. 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 \fIdsPtr\fR, the value of one of +\fBTcl_GetChannelOption\fR retrieves, in \fIoptionValue\fR, the value of one of the options currently in effect for a channel, or a list of all options and their values. The \fIchannel\fR argument identifies the channel for which to query an option or retrieve all options and their values. @@ -536,35 +604,33 @@ for the Tcl \fBsocket\fR command. 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 for an option on \fIchannel\fR. -\fIOptionName\fR is the option to set and \fInewValue\fR is the value to -set. +\fBTcl_SetChannelOption\fR sets a new value \fInewValue\fR +for an option \fIoptionName\fR on \fIchannel\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 \fIinterp->result\fR. - +\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. - -.VS 8.0 +.SH TCL_OUTPUTBUFFERED +.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. .SH "PLATFORM ISSUES" .PP The handles returned from \fBTcl_GetChannelHandle\fR depend on the @@ -574,13 +640,9 @@ call. On Windows platforms, the handle is a file \fBHANDLE\fR when 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. -.VE - +platforms. .SH "SEE ALSO" -DString(3), fconfigure(n), filename(n), fopen(2), Tcl_CreateChannel(3) - +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 |