This is an automatically generated page and cannot be edited directly. Text in Composite pages, (URLs starting with 'routine' or 'syntax') can be edited by clicking on the link labeled 'in context', and editing the text there.

Exit this popup by pressing <Escape>, or clicking on X or on the background.

while until
Combined from primary sources listed below.

In Control flow§

See primary documentation in context for while, until.

The while statement executes the block as long as its condition is true. So

my $x = 1;
while $x < 4 {
    print $x++;
}
print "\n";

# OUTPUT: «123␤»

Similarly, the until statement executes the block as long as the expression is false.

my $x = 1;
until $x > 3 {
    print $x++;
}
print "\n";

# OUTPUT: «123␤»

The condition for while or until can be parenthesized, but there must be a space between the keyword and the opening parenthesis of the condition.

Both while and until can be used as statement modifiers. E. g.

my $x = 42;
$x-- while $x > 12

Also see repeat/while and repeat/until below.

All these forms may produce a return value the same way loop does.