![]() |
Home / Documentation / 2.0 / API / | ![]() |
||
![]() ![]() ![]() |
||||
APR:PerlIO -- An APR Perl IO layer | ||||
![]() ![]() |
|
||
# under mod_perl use APR::PerlIO (); sub handler { my $r = shift; die "This Perl build doesn't support PerlIO layers" unless APR::PerlIO::PERLIO_LAYERS_ARE_ENABLED; open my $fh, ">:APR", $filename, $r->pool or die $!; # work with $fh as normal $fh close $fh; return Apache::OK; }
# outside mod_perl % perl -MApache2 -MAPR -MAPR::PerlIO -MAPR::Pool -le \ 'open my $fh, ">:APR", "/tmp/apr", APR::Pool->new or die "$!"; \ print $fh "whoah!"; \ close $fh;'
APR::PerlIO
implements a Perl IO layer using APR's file
manipulation as its internals.
Why do you want to use this? Normally you shouldn't, probably it won't be faster than Perl's default layer. It's only useful when you need to manipulate a filehandle opened at the APR side, while using Perl.
Normally you won't call open() with APR layer attribute, but some mod_perl functions will return a filehandle which is internally hooked to APR. But you can use APR Perl IO directly if you want.
Before using the Perl IO APR layer one has to check whether it's supported by the used perl build.
die "This Perl build doesn't support PerlIO layers" unless APR::PerlIO::PERLIO_LAYERS_ARE_ENABLED;
Notice that loading APR::PerlIO
won't fail when Perl IO layers
aren't available since APR::PerlIO
provides functionality for Perl
builds not supporting Perl IO layers.
To use APR Perl IO to open a file the four arguments open() should be used. For example:
open my $fh, ">:APR", $filename, $r->pool or die $!;
where:
the second argument is the mode to open the file, constructed from two
sections separated by the :
character: the first section is the
mode to open the file under (>, <, etc) and the second section
must be a string APR.
the fourth argument must be an APR::Pool
object.
the rest of the arguments are the same as described by the open() manpage.
seek($fh, $offset, $whence);
If $offset
is zero, seek()
works normally.
However if $offset
is non-zero and Perl has been compiled with with
large files support (-Duselargefiles
), whereas APR wasn't, this
function will croak. This is because largefile size Off_t
simply
cannot fit into a non-largefile size apr_off_t
.
To solve the problem, rebuild Perl with -Uuselargefiles
. Currently
there is no way to force APR to build with large files support.
The C API provides functions to convert between Perl IO and APR Perl IO filehandles.
META: document these
|
![]() |
![]() ![]() ![]() |