1FileCache(3pm)         Perl Programmers Reference Guide         FileCache(3pm)
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NAME

6       FileCache - keep more files open than the system permits
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SYNOPSIS

9           no strict 'refs';
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11           use FileCache;
12           # or
13           use FileCache maxopen => 16;
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15           cacheout $mode, $path;
16           # or
17           cacheout $path;
18           print $path @data;
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20           $fh = cacheout $mode, $path;
21           # or
22           $fh = cacheout $path;
23           print $fh @data;
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DESCRIPTION

26       The "cacheout" function will make sure that there's a filehandle open
27       for reading or writing available as the pathname you give it. It
28       automatically closes and re-opens files if you exceed your system's
29       maximum number of file descriptors, or the suggested maximum maxopen.
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31       cacheout EXPR
32           The 1-argument form of cacheout will open a file for writing ('>')
33           on it's first use, and appending ('>>') thereafter.
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35           Returns EXPR on success for convenience. You may neglect the return
36           value and manipulate EXPR as the filehandle directly if you prefer.
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38       cacheout MODE, EXPR
39           The 2-argument form of cacheout will use the supplied mode for the
40           initial and subsequent openings. Most valid modes for 3-argument
41           "open" are supported namely; '>', '+>', '<', '<+', '>>',  '|-'  and
42           '-|'
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44           To pass supplemental arguments to a program opened with  '|-'  or
45           '-|' append them to the command string as you would system EXPR.
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47           Returns EXPR on success for convenience. You may neglect the return
48           value and manipulate EXPR as the filehandle directly if you prefer.
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CAVEATS

51       While it is permissible to "close" a FileCache managed file, do not do
52       so if you are calling "FileCache::cacheout" from a package other than
53       which it was imported, or with another module which overrides "close".
54       If you must, use "FileCache::cacheout_close".
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56       Although FileCache can be used with piped opens ('-|' or '|-') doing so
57       is strongly discouraged.  If FileCache finds it necessary to close and
58       then reopen a pipe, the command at the far end of the pipe will be
59       reexecuted - the results of performing IO on FileCache'd pipes is
60       unlikely to be what you expect.  The ability to use FileCache on pipes
61       may be removed in a future release.
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63       FileCache does not store the current file offset if it finds it
64       necessary to close a file.  When the file is reopened, the offset will
65       be as specified by the original "open" file mode.  This could be
66       construed to be a bug.
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68       The module functionality relies on symbolic references, so things will
69       break under 'use strict' unless 'no strict "refs"' is also specified.
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BUGS

72       sys/param.h lies with its "NOFILE" define on some systems, so you may
73       have to set maxopen yourself.
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77perl v5.38.2                      2023-11-30                    FileCache(3pm)
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