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|
#!./perl -w
BEGIN {
chdir "t" if -d "t";
@INC = qw(. ../lib);
}
# Test srand.
use strict;
require "test.pl";
plan(tests => 10);
# Generate a load of random numbers.
# int() avoids possible floating point error.
sub mk_rand { map int rand 10000, 1..100; }
# Check that rand() is deterministic.
srand(1138);
my @first_run = mk_rand;
srand(1138);
my @second_run = mk_rand;
ok( eq_array(\@first_run, \@second_run), 'srand(), same arg, same rands' );
# Check that different seeds provide different random numbers
srand(31337);
@first_run = mk_rand;
srand(1138);
@second_run = mk_rand;
ok( !eq_array(\@first_run, \@second_run),
'srand(), different arg, different rands' );
# Check that srand() isn't affected by $_
{
local $_ = 42;
srand();
@first_run = mk_rand;
srand(42);
@second_run = mk_rand;
ok( !eq_array(\@first_run, \@second_run),
'srand(), no arg, not affected by $_');
}
# This test checks whether Perl called srand for you.
@first_run = `$^X -le "print int rand 100 for 1..100"`;
sleep(1); # in case our srand() is too time-dependent
@second_run = `$^X -le "print int rand 100 for 1..100"`;
ok( !eq_array(\@first_run, \@second_run), 'srand() called automatically');
# check srand's return value
my $seed = srand(1764);
is( $seed, 1764, "return value" );
$seed = srand(0);
ok( $seed, "true return value for srand(0)");
cmp_ok( $seed, '==', 0, "numeric 0 return value for srand(0)");
{
my @warnings;
my $b;
{
local $SIG{__WARN__} = sub {
push @warnings, "@_";
warn @_;
};
$b = $seed + 0;
}
is( $b, 0, "Quacks like a zero");
is( "@warnings", "", "Does not warn");
}
# [perl #40605]
{
use warnings;
my $w = '';
local $SIG{__WARN__} = sub { $w .= $_[0] };
srand(2**100);
like($w, qr/^Integer overflow in srand at /, "got a warning");
}
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