MirOS Manual: FileCache(3p)


FileCache(3p)   Perl Programmers Reference Guide    FileCache(3p)

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

perl v5.8.8                2005-02-05                           1

FileCache(3p)   Perl Programmers Reference Guide    FileCache(3p)

     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.

BUGS

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

perl v5.8.8                2005-02-05                           2

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