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Diffstat (limited to 'doc/OpenFileChnl.3')
| -rw-r--r-- | doc/OpenFileChnl.3 | 325 |
1 files changed, 196 insertions, 129 deletions
diff --git a/doc/OpenFileChnl.3 b/doc/OpenFileChnl.3 index c0d121c..e9205e3 100644 --- a/doc/OpenFileChnl.3 +++ b/doc/OpenFileChnl.3 @@ -4,13 +4,13 @@ '\" 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 1.2 1998/09/14 18:39:49 stanton Exp $ +'\" RCS: @(#) $Id: OpenFileChnl.3,v 1.3 1999/04/16 00:46:32 stanton Exp $ .so man.macros -.TH Tcl_OpenFileChannel 3 8.0 Tcl "Tcl Library Procedures" +.TH Tcl_OpenFileChannel 3 8.1 Tcl "Tcl Library Procedures" .BS '\" Note: do not modify the .SH NAME line immediately below! .SH NAME -Tcl_OpenFileChannel, Tcl_OpenCommandChannel, Tcl_MakeFileChannel, Tcl_GetChannel, Tcl_RegisterChannel, Tcl_UnregisterChannel, Tcl_Close, Tcl_Read, Tcl_Gets, Tcl_Write, Tcl_Flush, Tcl_Seek, Tcl_Tell, Tcl_Eof, Tcl_InputBlocked, Tcl_InputBuffered, Tcl_GetChannelOption, Tcl_SetChannelOption \- buffered I/O facilities using channels +Tcl_OpenFileChannel, Tcl_OpenCommandChannel, Tcl_MakeFileChannel, Tcl_GetChannel, 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 .SH SYNOPSIS .nf \fB#include <tcl.h>\fR @@ -22,7 +22,7 @@ Tcl_Channel .sp Tcl_Channel \fBTcl_OpenCommandChannel\fR(\fIinterp, argc, argv, flags\fR) -.VS +.VS 8.0 .sp Tcl_Channel \fBTcl_MakeFileChannel\fR(\fIhandle, readOrWrite\fR) @@ -40,17 +40,28 @@ int int \fBTcl_Close\fR(\fIinterp, channel\fR) .sp +.VS 8.1 int -\fBTcl_Read\fR(\fIchannel, buf, toRead\fR) +\fBTcl_ReadChars\fR(\fIchannel, readObjPtr, charsToRead, appendFlag\fR) .sp int -\fBTcl_Gets\fR(\fIchannel, lineRead\fR) +\fBTcl_Read\fR(\fIchannel, byteBuf, bytesToRead\fR) .sp int \fBTcl_GetsObj\fR(\fIchannel, lineObjPtr\fR) .sp int -\fBTcl_Write\fR(\fIchannel, buf, toWrite\fR) +\fBTcl_Gets\fR(\fIchannel, lineRead\fR) +.sp +int +\fBTcl_WriteObj\fR(\fIchannel, writeObjPtr\fR) +.sp +int +\fBTcl_WriteChars\fR(\fIchannel, charBuf, bytesToWrite\fR) +.sp +int +\fBTcl_Write\fR(\fIchannel, byteBuf, bytesToWrite\fR) +.VE .sp int \fBTcl_Flush\fR(\fIchannel\fR) @@ -83,37 +94,36 @@ Used for error reporting and to look up a channel registered in it. .AP char *fileName in The name of a local or network file. .AP 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. +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. .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. +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 -Arguments for constructing a command pipeline. -These values have the same meaning as the non-switch arguments -to the Tcl \fBexec\fR command. +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 Specifies the disposition of the stdio handles in pipeline: OR-ed -combination of \fBTCL_STDIN\fR, \fBTCL_STDOUT\fR, \fBTCL_STDERR\fR, -and \fBTCL_ENFORCE_MODE\fR. If \fBTCL_STDIN\fR is set, stdin for -the first child in the pipe is the pipe channel, otherwise it is the same -as the standard input of the invoking process; likewise for -\fBTCL_STDOUT\fR and \fBTCL_STDERR\fR. If \fBTCL_ENFORCE_MODE\fR is not set, -then the pipe can 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 +combination of \fBTCL_STDIN\fR, \fBTCL_STDOUT\fR, \fBTCL_STDERR\fR, and +\fBTCL_ENFORCE_MODE\fR. If \fBTCL_STDIN\fR is set, stdin for the first child +in the pipe is the pipe channel, otherwise it is the same as the standard +input of the invoking process; likewise for \fBTCL_STDOUT\fR and +\fBTCL_STDERR\fR. If \fBTCL_ENFORCE_MODE\fR is not set, then the pipe can +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 +The name of the channel. .VE .AP int *modePtr out Points at an integer variable that will receive an OR-ed combination of @@ -122,26 +132,40 @@ open for reading and writing. .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. -.AP char *buf in -An array of bytes in which to store channel input, or from which -to read channel output. -.AP int len in -The length of the input or output. -.AP int atEnd in -If nonzero, store the input at the end of the input queue, otherwise store -it at the head of the input queue. -.AP int toRead in -The number of bytes to read from the channel. -.AP Tcl_DString *lineRead in -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 Tcl_Obj *linePtrObj in +.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 +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. +.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 channel. The line read will be appended to the current value of the object. -.AP int toWrite in -The number of bytes to read from \fIbuf\fR and output to the channel. +.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 Tcl_Obj *writeObjPtr in +A pointer to a Tcl Object 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 +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 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 @@ -169,7 +193,7 @@ types. The channel mechanism is extensible to new channel types, by 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 modelled after +channel mechanism provides a buffering scheme modeled after Unix's standard I/O, and it also allows for nonblocking I/O on channels. .PP @@ -182,7 +206,7 @@ channels, see the manual entry for \fBTcl_CreateChannel\fR. .PP \fBTcl_OpenFileChannel\fR opens a file specified by \fIfileName\fR and returns a channel handle that can be used to perform input and output on -the file. This API is modelled after the \fBfopen\fR procedure of +the file. This API is modeled after the \fBfopen\fR procedure of the Unix standard I/O library. The syntax and meaning of all arguments is similar to those given in the Tcl \fBopen\fR command when opening a file. @@ -190,7 +214,7 @@ 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->result\fR after any error. +leaves an error message in \fIinterp\fR's result after any error. .PP The newly created channel is not registered in the supplied interpreter; to register it, use \fBTcl_RegisterChannel\fR, described below. @@ -310,93 +334,136 @@ left in \fIinterp->result\fR. .PP Note: it is not safe to call \fBTcl_Close\fR on a channel that has been registered using \fBTcl_RegisterChannel\fR; see the documentation for -\fBTcl_RegisterChannel\fR, above, for details. If the channel has ever been -given as the \fBchan\fR argument in a call to \fBTcl_RegisterChannel\fR, -you should instead use \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. +\fBTcl_RegisterChannel\fR, above, for details. If the channel has ever +been given as the \fBchan\fR argument in a call to +\fBTcl_RegisterChannel\fR, you should instead use +\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. -.SH TCL_READ -.PP -\fBTcl_Read\fR consumes up to \fItoRead\fR bytes of data from -\fIchannel\fR and stores it at \fIbuf\fR. -The return value of \fBTcl_Read\fR is the number of characters written -at \fIbuf\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. -If an error occurs, the return value is -1 and \fBTcl_Read\fR records -a POSIX error code that can be retrieved with \fBTcl_GetErrno\fR. -.PP -The return value may be smaller than the value of \fItoRead\fR, indicating -that less data than requested was available, also called a \fIshort -read\fR. -In blocking mode, this can only happen on an end-of-file. -In nonblocking mode, a short read can also occur if there is not -enough input currently available: \fBTcl_Read\fR returns a short -count rather than waiting for more data. -.PP -If the channel is in blocking mode, a return value of zero indicates an end -of file condition. If the channel is in nonblocking mode, a return value of -zero indicates either that no input is currently available or an end of -file condition. Use \fBTcl_Eof\fR and \fBTcl_InputBlocked\fR -to tell which of these conditions actually occurred. -.PP -\fBTcl_Read\fR translates platform-specific end-of-line representations -into the canonical \fB\en\fR internal representation according to the -current end-of-line recognition mode. End-of-line recognition and the -various platform-specific modes are described in the manual entry for the -Tcl \fBfconfigure\fR command. +.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 +return value is \-1 and \fBTcl_ReadChars\fR records a POSIX error code that +can be retrieved with \fBTcl_GetErrno\fR. +.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, +a short read can also occur if there is not enough input currently +available: \fBTcl_ReadChars\fR returns a short count rather than waiting +for more data. +.PP +If the channel is in blocking mode, a return value of zero indicates an +end-of-file condition. If the channel is in nonblocking mode, a return +value of zero indicates either that no input is currently available or an +end-of-file condition. Use \fBTcl_Eof\fR and \fBTcl_InputBlocked\fR to tell +which of these conditions actually occurred. +.PP +\fBTcl_ReadChars\fR translates the various end-of-line representations into +the canonical \fB\en\fR internal representation according to the current +end-of-line recognition mode. End-of-line recognition and the various +platform-specific modes are described in the manual entry for the Tcl +\fBfconfigure\fR command. +.PP +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 +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 +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. +Its contents are valid from the zeroth position up to and excluding the +position indicated by the return value. -.SH TCL_GETS AND TCL_GETSOBJ -.PP -\fBTcl_Gets\fR reads a line of input from a channel and appends all of -the characters of the line except for the terminating end-of-line character(s) -to the dynamic string given by \fIdsPtr\fR. -The end-of-line character(s) are read and discarded. +.SH TCL_GETSOBJ AND TCL_GETS +.PP +\fBTcl_GetsObj\fR consumes bytes from \fIchannel\fR, converting the bytes to +UTF-8 based on the channel's encoding, until a full line of input has been +seen. If the channel's encoding is \fBbinary\fR, each byte read from the +channel is treated as an individual Unicode character. All of the +characters of the line except for the terminating end-of-line character(s) +are appended to \fIlineObjPtr\fR's string representation. The end-of-line +character(s) are read and discarded. +.PP +If a line was successfully read, the return value is greater than or equal +to zero and indicates the number of bytes stored in \fIlineObjPtr\fR. If an +error occurs, \fBTcl_GetsObj\fR returns \-1 and records a POSIX error code +that can be retrieved with \fBTcl_GetErrno\fR. \fBTcl_GetsObj\fR also +returns \-1 if the end of the file is reached; the \fBTcl_Eof\fR procedure +can be used to distinguish an error from an end-of-file condition. +.PP +If the channel is in nonblocking mode, the return value can also be \-1 if +no data was available or the data that was available did not contain an +end-of-line character. When \-1 is returned, the \fBTcl_InputBlocked\fR +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. + +.SH TCL_WRITECHARS, TCL_WRITEOBJ, AND TCL_WRITE .PP -If a line was successfully read, the return value is greater than or -equal to zero, and it indicates the number of characters stored -in the dynamic string. -If an error occurs, \fBTcl_Gets\fR returns -1 and records a POSIX error -code that can be retrieved with \fBTcl_GetErrno\fR. -\fBTcl_Gets\fR also returns -1 if the end of the file is reached; -the \fBTcl_Eof\fR procedure can be used to distinguish an error -from an end-of-file condition. -.PP -If the channel is in nonblocking mode, the return value can also -be -1 if no data was available or the data that was available -did not contain an end-of-line character. -When -1 is returned, the \fBTcl_InputBlocked\fR procedure may be -invoked to determine if the channel is blocked because of input -unavailability. -.PP -\fBTcl_GetsObj\fR is the same as \fBTcl_Gets\fR except the resulting -characters are appended to a Tcl object \fBlineObjPtr\fR rather than a -dynamic string. -.SH TCL_WRITE -.PP -\fBTcl_Write\fR accepts \fItoWrite\fR bytes of data at \fIbuf\fR for output -on \fIchannel\fR. This data may not appear on the output device -immediately. If the data should appear immediately, call \fBTcl_Flush\fR -after the call to \fBTcl_Write\fR, or set the \fB-buffering\fR option on -the channel to \fBnone\fR. If you wish the data to appear as soon as an end -of line is accepted for output, set the \fB\-buffering\fR option on the -channel to \fBline\fR mode. -.PP -The \fItoWrite\fR argument specifies how many bytes of data are provided in -the \fIbuf\fR argument. If it is negative, \fBTcl_Write\fR expects the data +\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. .PP -The return value of \fBTcl_Write\fR is a count of how many -characters were accepted for output to the channel. This is either equal to -\fItoWrite\fR or -1 to indicate that an error occurred. -If an error occurs, \fBTcl_Write\fR also records a POSIX error code -that may be retrieved with \fBTcl_GetErrno\fR. +Data queued for output may not appear on the output device immediately, due +to internal buffering. If the data should appear immediately, call +\fBTcl_Flush\fR after the call to \fBTcl_WriteChars\fR, or set the +\fB\-buffering\fR option on the channel to \fBnone\fR. If you wish the data +to appear as soon as a complete line is accepted for output, set the +\fB\-buffering\fR option on the channel to \fBline\fR mode. +.PP +The return value of \fBTcl_WriteChars\fR is a count of how many bytes were +accepted for output to the channel. This is either greater than zero to +indicate success or \-1 to indicate that an error occurred. If an error +occurs, \fBTcl_WriteChars\fR records a POSIX error code that may be +retrieved with \fBTcl_GetErrno\fR. .PP Newline characters in the output data are translated to platform-specific -end-of-line sequences according to the \fB\-translation\fR option for -the channel. +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 +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-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 +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 .SH TCL_FLUSH .PP @@ -419,14 +486,14 @@ data will be read or written. Buffered output is flushed to the channel and buffered input is discarded, prior to the seek operation. .PP \fBTcl_Seek\fR normally returns the new access point. -If an error occurs, \fBTcl_Seek\fR returns -1 and records a POSIX error +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. +value is \-1 if the channel does not support seeking. .SH TCL_GETCHANNELOPTION .PP @@ -477,7 +544,7 @@ The call always returns zero if the channel is in blocking mode. buffered in the internal buffers for a channel. If the channel is not open for reading, this function always returns zero. -.VS +.VS 8.0 .SH "PLATFORM ISSUES" .PP The handles returned from \fBTcl_GetChannelHandle\fR depend on the |