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-rw-r--r--doc/binary.n26
1 files changed, 21 insertions, 5 deletions
diff --git a/doc/binary.n b/doc/binary.n
index a40afe6..cbbebd1 100644
--- a/doc/binary.n
+++ b/doc/binary.n
@@ -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
@@ -95,13 +102,14 @@ between Unix systems and on USENET, but is less common these days, having been
largely superseded by the \fBbase64\fR binary encoding.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"
@@ -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), tcl_platform(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: