Re^3: open(): Is there a simple way to map between numeric open modes and "symbol modes"?

[Anonymous Monk]

See also FileHandle::Fmode and Fcntl

#!/usr/bin/perl --
use strict; use warnings; use Data::Dump;
use Fcntl();
my %mode2symbol = (
#~     Fcntl::F_DUPFD()  => '&',
    Fcntl::O_RDONLY() => '<',
    Fcntl::O_RDWR()   => '+<',
    Fcntl::O_TRUNC()  => '>',
    Fcntl::O_WRONLY() => '>',
    Fcntl::O_APPEND() => '>>',
    Fcntl::O_CREAT()  => '>',
);

my %name2mode = (
#~     F_DUPFD  => Fcntl::F_DUPFD(),
    O_RDONLY => Fcntl::O_RDONLY(),
    O_RDWR   => Fcntl::O_RDWR(),
    O_TRUNC  => Fcntl::O_TRUNC(),
    O_WRONLY => Fcntl::O_WRONLY(),
    O_APPEND => Fcntl::O_APPEND(),
    O_CREAT  => Fcntl::O_CREAT(),
);

$mode2symbol{ $name2mode{O_RDWR} | $name2mode{O_APPEND} } = '+>>';
$mode2symbol{ $name2mode{O_RDONLY} | $name2mode{O_APPEND} } = '+>>';
$mode2symbol{ $name2mode{O_WRONLY} | $name2mode{O_APPEND} } = '+>>';

dd \%mode2symbol;
dd \%name2mode;
__END__
{
  "0"   => "<",
  "1"   => ">",
  "2"   => "+<",
  "8"   => "+>>",
  "9"   => "+>>",
  "10"  => "+>>",
  "256" => ">",
  "512" => ">",
}
{
  O_APPEND => 8,
  O_CREAT  => 256,
  O_RDONLY => 0,
  O_RDWR   => 2,
  O_TRUNC  => 512,
  O_WRONLY => 1,
}