diff options
Diffstat (limited to 'doc/binary.n')
| -rw-r--r-- | doc/binary.n | 32 |
1 files changed, 24 insertions, 8 deletions
diff --git a/doc/binary.n b/doc/binary.n index 8133829..014704d 100644 --- a/doc/binary.n +++ b/doc/binary.n @@ -5,8 +5,8 @@ '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. '\" -.so man.macros .TH binary n 8.0 Tcl "Tcl Built-In Commands" +.so man.macros .BS '\" Note: do not modify the .SH NAME line immediately below! .SH NAME @@ -36,6 +36,13 @@ The \fBbinary encode\fR and \fBbinary decode\fR subcommands convert binary data to or from string encodings such as base64 (used in MIME messages for example). .VE 8.6 +.PP +Note that other operations on binary data, such as taking a subsequence of it, +getting its length, or reinterpreting it as a string in some encoding, are +done by other Tcl commands (respectively \fBstring range\fR, +\fBstring length\fR and \fBencoding convertfrom\fR in the example cases). A +binary string in Tcl is merely one where all the characters it contains are in +the range \eu0000\-\eu00FF. .SH "BINARY ENCODE AND DECODE" .VS 8.6 .PP @@ -92,16 +99,17 @@ Instructs the decoder to throw an error if it encounters whitespace characters. . The \fBuuencode\fR binary encoding used to be common for transfer of data between Unix systems and on USENET, but is less common these days, having been -largely superceded by the \fBbase64\fR binary encoding. +largely superseded by the \fBbase64\fR binary encoding. .RS .PP -During encoding, the following options are supported: -'\" This is wrong! The uuencode format had more complexity than this! +During encoding, the following options are supported (though changing them may +produce files that other implementations of decoders cannot process): .TP \fB\-maxlen \fIlength\fR . Indicates that the output should be split into lines of no more than -\fIlength\fR characters. By default, lines are not split. +\fIlength\fR characters. By default, lines are split every 61 characters, and +this must be in the range 3 to 85 due to limitations in the encoding. .TP \fB\-wrapchar \fIcharacter\fR . @@ -114,7 +122,11 @@ During decoding, the following options are supported: .TP \fB\-strict\fR . -Instructs the decoder to throw an error if it encounters whitespace characters. Otherwise it ignores them. +Instructs the decoder to throw an error if it encounters unexpected whitespace +characters. Otherwise it ignores them. +.PP +Note that neither the encoder nor the decoder handle the header and footer of +the uuencode format. .RE .VE 8.6 .SH "BINARY FORMAT" @@ -135,7 +147,7 @@ is a non-negative decimal integer or \fB*\fR, which normally indicates that all of the items in the value are to be used. If the number of arguments does not match the number of fields in the format string that consume arguments, then an error is generated. The flag character -is ignored for for \fBbinary format\fR. +is ignored for \fBbinary format\fR. .PP Here is a small example to clarify the relation between the field specifiers and the arguments: @@ -855,6 +867,7 @@ architectures, use their textual representation (as produced by .PP This is a procedure to write a Tcl string to a binary-encoded channel as UTF-8 data preceded by a length word: +.PP .CS proc \fIwriteString\fR {channel string} { set data [encoding convertto utf-8 $string] @@ -865,6 +878,7 @@ proc \fIwriteString\fR {channel string} { .PP This procedure reads a string from a channel that was written by the previously presented \fIwriteString\fR procedure: +.PP .CS proc \fIreadString\fR {channel} { if {![\fBbinary scan\fR [read $channel 4] I length]} { @@ -877,6 +891,7 @@ proc \fIreadString\fR {channel} { .PP This converts the contents of a file (named in the variable \fIfilename\fR) to base64 and prints them: +.PP .CS set f [open $filename rb] set data [read $f] @@ -884,9 +899,10 @@ close $f puts [\fBbinary encode\fR base64 \-maxlen 64 $data] .CE .SH "SEE ALSO" -format(n), scan(n), tclvars(n) +encoding(n), format(n), scan(n), string(n), tcl_platform(n) .SH KEYWORDS binary, format, scan '\" Local Variables: '\" mode: nroff +'\" fill-column: 78 '\" End: |