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FileHandle::Fmode
determine whether a filehandle is opened for reading, writing, or both.

FileHandle::Fmode - determine whether a filehandle is opened for reading, writing, or both.


NAME




FileHandle::Fmode - determine whether a filehandle is opened for reading, writing, or both.


SYNOPSIS




 use FileHandle::Fmode qw(:all);

 .

 .

 #$fh and FH are open filehandles

 print is_R($fh), "\n";

 print is_W(\*FH), "\n";


FUNCTIONS


 $bool = is_FH($fh);

 $bool = is_FH(\*FH);

  This is just a (more intuitively named) alias for is_arg_ok().

  Returns 1 if its argument is an open filehandle.

  Returns 0 if its argument is something other than an open filehandle.

 $bool = is_arg_ok($fh);

 $bool = is_arg_ok(\*FH);

  Returns 1 if its argument is an open filehandle.

  Returns 0 if its argument is something other than an open filehandle.

 Arguments to the following functions  must be open filehandles. If 

 any of those functions receive an argument that is not an open 

 filehandle then the function dies with an appropriate error message.

 To ensure that your script won't suffer such a death, you could first

 check by passing the argument to is_FH(). Or you could wrap the

 function call in an eval{} block.

 $bool = is_R($fh);

 $bool = is_R(\*FH);

  Returns true if the filehandle is readable.

  Else returns false.

 $bool = is_W($fh);

 $bool = is_W(\*FH);

  Returns true if the filehandle is writable.

  Else returns false

 $bool = is_RO($fh);

 $bool = is_RO(\*FH);

  Returns true if the filehandle is readable but not writable.

  Else returns false

 $bool = is_WO($fh);

 $bool = is_WO(\*FH);

  Returns true if the filehandle is writable but not readable.

  Else returns false

 $bool = is_RW($fh);

 $bool = is_RW(\*FH);

  Returns true if the filehandle is both readable and writable.

  Else returns false

 $bool = is_A($fh);

 $bool = is_A(\*FH);

  Returns true if the filehandle was opened for appending.

  Else returns false.

  Not currently implemented on Win32 with pre-5.6.1 versions of perl (and  

  dies with appropriate error message if called on such a platform).



=head1 CREDITS



 Inspired (hmmm ... is that the right word ?) by an idea from BrowserUK

 posted on PerlMonks in response to a question from dragonchild. Win32

 code (including XS code) provided by BrowserUK. Zaxo presented the idea 

 of using fcntl() in an earlier PerlMonks thread.

 Thanks to dragonchild and BrowserUK for steering this module in

 the right direction.

 Thanks to attn.steven.kuo for directing me to the perliol routines

 that enable us to query filehandles attached to memory objects.

 And thanks to Jost Krieger for helping to sort out the test failures that

 were occurring on Solaris (and some other operating systems too).



=head1 TODO

 I don't know that anyone still runs pre-5.6.1 perl on Win32. However, if

 someone likes to tell me how is_A() could be made to work on pre-5.6.1

 Win32 perl, I would be quite happy to implement it.



=head1 LICENSE



 This program is free software; you may redistribute it and/or 

 modify it under the same terms as Perl itself.


AUTHOR




 Sisyphus <sisyphus at cpan dot org>
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