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

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

NNAAMMEE #

 FileCache - keep more files open than the system permits

SSYYNNOOPPSSIISS #

     no strict 'refs';

     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;

DDEESSCCRRIIPPTTIIOONN #

 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 _m_a_x_o_p_e_n.

 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.

CCAAVVEEAATTSS #

 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.

 The module functionality relies on symbolic references, so things will
 break under 'use strict' unless 'no strict "refs"' is also specified.

BBUUGGSS #

 _s_y_s_/_p_a_r_a_m_._h lies with its "NOFILE" define on some systems, so you may
 have to set _m_a_x_o_p_e_n yourself.

perl v5.36.3 2019-02-13 FileCache(3p)