FileCache.pdf

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Perl version 5.10.0 documentation - FileCache
NAME
FileCache - keep more files open than the system permits
SYNOPSIS
use FileCache;
# or
use FileCache maxopen => 16;
cacheout $mode, $path;
# or
cacheout $path;
print $path @data;
$fh = cacheout $mode, $path;
# or
$fh = cacheout $path;
print $fh @data;
DESCRIPTION
The
cacheout
function will make sure that there's a filehandle open for reading or writing available
as the pathname you give it. It automatically closes and re-opens files if you exceed your system's
maximum number of file descriptors, or the suggested maximum
maxopen.
cacheout EXPR
The 1-argument form of cacheout will open a file for writing ('>') on it's first use, and
appending ('>>') thereafter.
Returns EXPR on success for convenience. You may neglect the return value and manipulate
EXPR as the filehandle directly if you prefer.
cacheout MODE, EXPR
The 2-argument form of cacheout will use the supplied mode for the initial and subsequent
openings. Most valid modes for 3-argument
open
are supported namely;
'>', '+>', '<',
'<+', '>>', '|-'
and
'-|'
To pass supplemental arguments to a program opened with
'|-'
or
'-|'
append them
to the command string as you would system EXPR.
Returns EXPR on success for convenience. You may neglect the return value and manipulate
EXPR as the filehandle directly if you prefer.
CAVEATS
While it is permissible to
close
a FileCache managed file, do not do so if you are calling
FileCache::cacheout
from a package other than which it was imported, or with another module
which overrides
close.
If you must, use
FileCache::cacheout_close.
Although FileCache can be used with piped opens ('-|' or '|-') doing so is strongly discouraged. If
FileCache finds it necessary to close and then reopen a pipe, the command at the far end of the pipe
will be reexecuted - the results of performing IO on FileCache'd pipes is unlikely to be what you
expect. The ability to use FileCache on pipes may be removed in a future release.
FileCache does not store the current file offset if it finds it necessary to close a file. When the file is
reopened, the offset will be as specified by the original
open
file mode. This could be construed to be
a bug.
http://perldoc.perl.org
Page 1
Perl version 5.10.0 documentation - FileCache
BUGS
sys/param.h
lies with its
NOFILE
define on some systems, so you may have to set
maxopen
yourself.
http://perldoc.perl.org
Page 2

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