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| author | Father Chrysostomos <sprout@cpan.org> | 2011-02-22 12:57:00 -0800 |
|---|---|---|
| committer | Father Chrysostomos <sprout@cpan.org> | 2011-02-22 17:46:50 -0800 |
| commit | a7c1632ddd60f69c0d947987c4c8a59f2cd23e63 (patch) | |
| tree | 17faac0cb018d3cdc99a29e96b0a2660ab420387 /pod/perlfunc.pod | |
| parent | dbfe1e81aad2393c90668c6aee3fb9d47133361d (diff) | |
| download | perl-a7c1632ddd60f69c0d947987c4c8a59f2cd23e63.tar.gz | |
perlfunc/fileno: Document the -1 retval
Diffstat (limited to 'pod/perlfunc.pod')
| -rw-r--r-- | pod/perlfunc.pod | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/pod/perlfunc.pod b/pod/perlfunc.pod index 149c44b6cc..891d938300 100644 --- a/pod/perlfunc.pod +++ b/pod/perlfunc.pod @@ -1938,7 +1938,11 @@ on your own, though. X<fileno> Returns the file descriptor for a filehandle, or undefined if the -filehandle is not open. This is mainly useful for constructing +filehandle is not open. If there is no real file descriptor at the OS +level, as can happen with filehandles connected to memory objects via +C<open> with a reference for the third argument, -1 is returned. + +This is mainly useful for constructing bitmaps for C<select> and low-level POSIX tty-handling operations. If FILEHANDLE is an expression, the value is taken as an indirect filehandle, generally its name. @@ -1950,10 +1954,6 @@ same underlying descriptor: print "THIS and THAT are dups\n"; } -(Filehandles connected to memory objects via new features of C<open> may -return undefined even though they are open.) - - =item flock FILEHANDLE,OPERATION X<flock> X<lock> X<locking> |