MAN page from Mandriva 2007 perl-5.8.8-7.1mdv2007.0.i586.rpm

FileCache

Section: Perl Programmers Reference Guide (3pm)
Updated: 2001-09-21
Index

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 openfor reading or writing available as the pathname you give it. Itautomatically closes and re-opens files if you exceed your system'smaximum 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 thereturn 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 initialand subsequent openings. Most valid modes for 3-argument "open" are supportednamely; '>', '+>', '<', '<+', '>>', '|-' 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 thereturn 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 otherthan 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 isstrongly discouraged. If FileCache finds it necessary to close and then reopena pipe, the command at the far end of the pipe will be reexecuted - the resultsof performing IO on FileCache'd pipes is unlikely to be what you expect. Theability 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 toclose a file. When the file is reopened, the offset will be as specified by theoriginal "open" file mode. This could be construed to be a bug.

BUGS

sys/param.h lies with its "NOFILE" define on some systems,so you may have to set maxopen yourself.

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