The "decoct()" function converts a decimal number to octal number.

    decoct(dec_number)

In the above syntax "dec_number" is the decimal number to be converted to octal number.

    <?php
    echo decoct(10) . "\n";
    echo decoct(15);
    ?>

    12
    17

In the above example the decimal numbers "10","15" are converted to octal numbers "12","17".