PHP 7.0.6 Released

    gmp_testbit

    (PHP 5 >= 5.3.0, PHP 7)

    gmp_testbit — Tests if a bit is set

    Description

    bool gmp_testbit ( GMP $a , int $index )

    Tests if the specified bit is set.

    Parameters

    a

    Either a GMP number resource in PHP 5.5 and earlier, a GMP object in PHP 5.6 and later, or a numeric string provided that it is possible to convert the latter to a number.

    index

    The bit to test

    Return Values

    Returns TRUE if the bit is set in resource $a, otherwise FALSE.

    Errors/Exceptions

    An E_WARNING level error is issued when index is less than zero, and FALSE is returned.

    Examples

    Example #1 gmp_testbit() example

    <?php
    $n     = gmp_init("1000000");
    var_dump(gmp_testbit($n, 1));
    gmp_setbit($n, 1);
    var_dump(gmp_testbit($n, 1));
    ?>

    The above example will output:

    bool(false)
bool(true)

    See Also

    User Contributed Notes

    bluej100@gmail
    8 years ago
    gmp_testbit will be very useful for my (over 64-bit) bitmask checking.

    In the meantime, I think these are the best replacements.

    Mostly full:

    <?php
    (gmp_scan1($a, $index) == $index)
    ?>

    Mostly empty:

    <?php
    (gmp_scan0($a, $index) != $index)
    ?>

    Still worst-case O(N), though.
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