packed address of the appropriate type for the socket. See the examples in
L<perlipc/"Sockets: Client/Server Communication">.
-=item binmode FILEHANDLE, DISCIPLINE
+=item binmode FILEHANDLE, LAYER
=item binmode FILEHANDLE
taken as the name of the filehandle. Returns true on success,
C<undef> on failure.
-If DISCIPLINE is omitted or specified as C<:raw> the filehandle is made
+If LAYER is omitted or specified as C<:raw> the filehandle is made
suitable for passing binary data. This includes turning off possible CRLF
translation and marking it as bytes (as opposed to Unicode characters).
Note that as desipite what may be implied in I<"Programming Perl">
(the Camel) or elsewhere C<:raw> is I<not> the simply inverse of C<:crlf>
-- other disciplines which would affect binary nature of the stream are
+-- other layers which would affect binary nature of the stream are
I<also> disabled. See L<PerlIO>, L<perlrun> and the discussion about the
PERLIO environment variable.
+I<The LAYER parameter of the binmode() function is described as "DISCIPLINE"
+in "Programming Perl, 3rd Edition". However, since the publishing of this
+book, by many known as "Camel III", the consensus of the naming of this
+functionality has moved from "discipline" to "layer". All documentation
+of this version of Perl therefore refers to "layers" rather than to
+"disciplines". Now back to the regularly scheduled documentation...>
+
On some systems (in general, DOS and Windows-based systems) binmode()
is necessary when you're not working with a text file. For the sake
of portability it is a good idea to always use it when appropriate,
In other words: regardless of platform, use binmode() on binary files
(like for example images).
-If DISCIPLINE is present it is a single string, but may contain
+If LAYER is present it is a single string, but may contain
multiple directives. The directives alter the behaviour of the
-file handle. When DISCIPLINE is present using binmode on text
+file handle. When LAYER is present using binmode on text
file makes sense.
To mark FILEHANDLE as UTF-8, use C<:utf8>.
The C<:bytes>, C<:crlf>, and C<:utf8>, and any other directives of the
-form C<:...>, are called I/O I<disciplines>. The normal implementation
-of disciplines in Perl 5.8 and later is in terms of I<layers>. See
-L<PerlIO>. (There is typically a one-to-one correspondence between
-layers and disiplines.) The C<open> pragma can be used to establish
-default I/O disciplines. See L<open>.
+form C<:...>, are called I/O I<layers>. The C<open> pragma can be used to
+establish default I/O layers. See L<open>.
In general, binmode() should be called after open() but before any I/O
is done on the filehandle. Calling binmode() will normally flush any
pending buffered output data (and perhaps pending input data) on the
-handle. An exception to this is the C<:encoding> discipline that
+handle. An exception to this is the C<:encoding> layer that
changes the default character encoding of the handle, see L<open>.
-The C<:encoding> discipline sometimes needs to be called in
+The C<:encoding> layer sometimes needs to be called in
mid-stream, and it doesn't flush the stream.
The operating system, device drivers, C libraries, and Perl run-time
In the 2-arguments (and 1-argument) form opening C<'-'> opens STDIN
and opening C<< '>-' >> opens STDOUT.
-You may use the three-argument form of open to specify
-I<I/O disciplines> or IO "layers" to be applied to the handle that affect how the input and output
-are processed: (see L<open> and L<PerlIO> for more details).
-For example
+You may use the three-argument form of open to specify IO "layers"
+(sometimes also referred to as "disciplines") to be applied to the handle
+that affect how the input and output are processed (see L<open> and
+L<PerlIO> for more details). For example
open(FH, "<:utf8", "file")
will open the UTF-8 encoded file containing Unicode characters,
-see L<perluniintro>. (Note that if disciplines are specified in the
-three-arg form then default disciplines set by the C<open> pragma are
+see L<perluniintro>. (Note that if layers are specified in the
+three-arg form then default layers set by the C<open> pragma are
ignored.)
Open returns nonzero upon success, the undefined value otherwise. If
Note the I<characters>: depending on the status of the filehandle,
either (8-bit) bytes or characters are read. By default all
filehandles operate on bytes, but for example if the filehandle has
-been opened with the C<:utf8> discipline (see L</open>, and the C<open>
+been opened with the C<:utf8> I/O layer (see L</open>, and the C<open>
pragma, L<open>), the I/O will operate on characters, not bytes.
=item readdir DIRHANDLE
Note the I<characters>: depending on the status of the socket, either
(8-bit) bytes or characters are received. By default all sockets
operate on bytes, but for example if the socket has been changed using
-binmode() to operate with the C<:utf8> discipline (see the C<open>
+binmode() to operate with the C<:utf8> I/O layer (see the C<open>
pragma, L<open>), the I/O will operate on characters, not bytes.
=item redo LABEL
Note the I<in bytes>: even if the filehandle has been set to
operate on characters (for example by using the C<:utf8> open
-discipline), tell() will return byte offsets, not character offsets
+layer), tell() will return byte offsets, not character offsets
(because implementing that would render seek() and tell() rather slow).
If you want to position file for C<sysread> or C<syswrite>, don't use
Note the I<characters>: depending on the status of the socket, either
(8-bit) bytes or characters are sent. By default all sockets operate
on bytes, but for example if the socket has been changed using
-binmode() to operate with the C<:utf8> discipline (see L</open>, or
+binmode() to operate with the C<:utf8> I/O layer (see L</open>, or
the C<open> pragma, L<open>), the I/O will operate on characters, not
bytes.
Note the I<characters>: depending on the status of the filehandle,
either (8-bit) bytes or characters are read. By default all
filehandles operate on bytes, but for example if the filehandle has
-been opened with the C<:utf8> discipline (see L</open>, and the C<open>
+been opened with the C<:utf8> I/O layer (see L</open>, and the C<open>
pragma, L<open>), the I/O will operate on characters, not bytes.
An OFFSET may be specified to place the read data at some place in the
negative).
Note the I<in bytes>: even if the filehandle has been set to operate
-on characters (for example by using the C<:utf8> discipline), tell()
+on characters (for example by using the C<:utf8> I/O layer), tell()
will return byte offsets, not character offsets (because implementing
that would render sysseek() very slow).
Note the I<characters>: depending on the status of the filehandle,
either (8-bit) bytes or characters are written. By default all
filehandles operate on bytes, but for example if the filehandle has
-been opened with the C<:utf8> discipline (see L</open>, and the open
+been opened with the C<:utf8> I/O layer (see L</open>, and the open
pragma, L<open>), the I/O will operate on characters, not bytes.
=item tell FILEHANDLE
Note the I<in bytes>: even if the filehandle has been set to
operate on characters (for example by using the C<:utf8> open
-discipline), tell() will return byte offsets, not character offsets
+layer), tell() will return byte offsets, not character offsets
(because that would render seek() and tell() rather slow).
The return value of tell() for the standard streams like the STDIN
projects / p5sagit/p5-mst-13.2.git / blobdiff