Based on the C<:perlio> layer.
-=item :mmap
-
-A layer which implements "reading" of files by using C<mmap()> to
-make a (whole) file appear in the process's address space, and then
-using that as PerlIO's "buffer". This I<may> be faster in certain
-circumstances for large files, and may result in less physical memory
-use when multiple processes are reading the same file.
-
-Files which are not C<mmap()>-able revert to behaving like the C<:perlio>
-layer. Writes also behave like the C<:perlio> layer, as C<mmap()> for write
-needs extra house-keeping (to extend the file) which negates any advantage.
-
-The C<:mmap> layer will not exist if the platform does not support C<mmap()>.
-
=item :utf8
Declares that the stream accepts perl's I<internal> encoding of
an C<:encoding> also enables C<:utf8>. See L<PerlIO::encoding>
for more information.
+=item :mmap
+
+A layer which implements "reading" of files by using C<mmap()> to
+make a (whole) file appear in the process's address space, and then
+using that as PerlIO's "buffer". This I<may> be faster in certain
+circumstances for large files, and may result in less physical memory
+use when multiple processes are reading the same file.
+
+Files which are not C<mmap()>-able revert to behaving like the C<:perlio>
+layer. Writes also behave like the C<:perlio> layer, as C<mmap()> for write
+needs extra house-keeping (to extend the file) which negates any advantage.
+
+The C<:mmap> layer will not exist if the platform does not support C<mmap()>.
+
=item :via
Use C<:via(MODULE)> either in open() or binmode() to install a layer
unset / "" unix perlio / stdio [1] unix crlf
stdio unix perlio / stdio [1] stdio
perlio unix perlio unix perlio
- mmap unix mmap unix mmap
# [1] "stdio" if Configure found out how to do "fast stdio" (depends
# on the stdio implementation) and in Perl 5.8, otherwise "unix perlio"