Reimplement $[ as a module

[perl5.git] / t / op / sselect.t

#!./perl

my $hires;
BEGIN {
    chdir 't' if -d 't';
    @INC = ('.', '../lib');
    $hires = eval 'use Time::HiResx "time"; 1';
}

require 'test.pl';

plan (11);

my $blank = "";
eval {select undef, $blank, $blank, 0};
is ($@, "", 'select undef  $blank $blank 0');
eval {select $blank, undef, $blank, 0};
is ($@, "", 'select $blank undef  $blank 0');
eval {select $blank, $blank, undef, 0};
is ($@, "", 'select $blank $blank undef  0');

eval {select "", $blank, $blank, 0};
is ($@, "", 'select ""     $blank $blank 0');
eval {select $blank, "", $blank, 0};
is ($@, "", 'select $blank ""     $blank 0');
eval {select $blank, $blank, "", 0};
is ($@, "", 'select $blank $blank ""     0');

eval {select "a", $blank, $blank, 0};
like ($@, qr/^Modification of a read-only value attempted/,
	    'select "a"    $blank $blank 0');
eval {select $blank, "a", $blank, 0};
like ($@, qr/^Modification of a read-only value attempted/,
	    'select $blank "a"    $blank 0');
eval {select $blank, $blank, "a", 0};
like ($@, qr/^Modification of a read-only value attempted/,
	    'select $blank $blank "a"    0');

my $sleep = 3;
# Actual sleep time on Windows may be rounded down to an integral
# multiple of the system clock tick interval.  Clock tick interval
# is configurable, but usually about 15.625 milliseconds.
# time() however (if we haven;t loaded Time::HiRes), doesn't return
# fractional values, so the observed delay may be 1 second short.
#
# There is also a report that old linux kernels may return 0.5ms early:
# <20110520081714.GC17549@mars.tony.develop-help.com>.
#

my $under = $hires ? 0.1 : 1;

my $t0 = time;
select(undef, undef, undef, $sleep);
my $t1 = time;
my $diff = $t1-$t0;
ok($diff >= $sleep-$under, "select(u,u,u,\$sleep):  at least $sleep seconds have passed");
note("diff=$diff under=$under");

my $empty = "";
vec($empty,0,1) = 0;
$t0 = time;
select($empty, undef, undef, $sleep);
$t1 = time;
$diff = $t1-$t0;
ok($diff >= $sleep-$under, "select(\$e,u,u,\$sleep): at least $sleep seconds have passed");
note("diff=$diff under=$under");