source: vendor/perl/5.8.8/t/io/binmode.t

#!./perl -w

BEGIN {
    chdir 't' if -d 't';
    @INC = qw(. ../lib);
    require './test.pl';
}

use Config;
BEGIN {
    eval {require Errno; Errno->import;};
}
plan(tests => 9);

ok( binmode(STDERR),            'STDERR made binary' );
if (find PerlIO::Layer 'perlio') {
  ok( binmode(STDERR, ":unix"),   '  with unix discipline' );
} else {
  ok(1,   '  skip unix discipline without PerlIO layers' );
}
ok( binmode(STDERR, ":raw"),    '  raw' );
ok( binmode(STDERR, ":crlf"),   '  and crlf' );

# If this one fails, we're in trouble.  So we just bail out.
ok( binmode(STDOUT),            'STDOUT made binary' )      || exit(1);
if (find PerlIO::Layer 'perlio') {
  ok( binmode(STDOUT, ":unix"),   '  with unix discipline' );
} else {
  ok(1,   '  skip unix discipline without PerlIO layers' );
}
ok( binmode(STDOUT, ":raw"),    '  raw' );
ok( binmode(STDOUT, ":crlf"),   '  and crlf' );

SKIP: {
    skip "minitest", 1 if $ENV{PERL_CORE_MINITEST};
    skip "no EBADF", 1 if (!exists &Errno::EBADF);

    no warnings 'io', 'once';
    $! = 0;
    binmode(B);
    ok($! == &Errno::EBADF);
}