GMP_SETBIT(3) 1 GMP_SETBIT(3)
gmp_setbit - Set bit
SYNOPSIS
void gmp_setbit (GMP &$a, int $index, [bool $bit_on = true])
DESCRIPTION
Sets bit $index in $a.
PARAMETERS
o $a
- The value to modify. 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.
o $index
- The index of the bit to set. Index 0 represents the least significant bit.
o $bit_on
- True to set the bit (set it to 1/on); false to clear the bit (set it to 0/off).
RETURN VALUES
A GMP number resource in PHP 5.5 and earlier, or a GMP object in PHP 5.6 and later.
EXAMPLES
Example #1
gmp_setbit(3) example - 0 index
<?php
$a = gmp_init("2"); //
echo gmp_strval($a), ' -> 0b', gmp_strval($a, 2), "
";
gmp_setbit($a, 0); // 0b10 now becomes 0b11
echo gmp_strval($a), ' -> 0b', gmp_strval($a, 2), "
";
?>
The above example will output:
2 -> 0b10
3 -> 0b11
Example #2
gmp_setbit(3) example - 1 index
<?php
$a = gmp_init("0xfd");
echo gmp_strval($a), ' -> 0b', gmp_strval($a, 2), "
";
gmp_setbit($a, 1); // index starts at 0
echo gmp_strval($a), ' -> 0b', gmp_strval($a, 2), "
";
?>
The above example will output:
253 -> 0b11111101
255 -> 0b11111111
Example #3
gmp_setbit(3) example - clearing a bit
<?php
$a = gmp_init("0xff");
echo gmp_strval($a), ' -> 0b', gmp_strval($a, 2), "
";
gmp_setbit($a, 0, false); // clear bit at index 0
echo gmp_strval($a), ' -> 0b', gmp_strval($a, 2), "
";
?>
The above example will output:
255 -> 0b11111111
254 -> 0b11111110
NOTES
Note
Unlike most of the other GMP functions, gmp_setbit(3) must be called with a GMP resource that already exists (using gmp_init(3) for
example). One will not be automatically created.
SEE ALSO
gmp_clrbit(3), gmp_testbit(3).
PHP Documentation Group GMP_SETBIT(3)