(PHP 4 >= 4.0.4, PHP 5, PHP 7)
gmp_setbit — Set bit
aThe value to modify.
锟斤拷锟斤拷锟斤拷一锟斤拷 GMP 锟斤拷锟斤拷 resouce锟斤拷锟斤拷一锟斤拷锟斤拷锟斤拷转锟斤拷为锟斤拷值锟斤拷锟街凤拷锟斤拷锟斤拷
indexThe index of the bit to set. Index 0 represents the least significant bit.
bit_onTrue to set the bit (set it to 1/on); false to clear the bit (set it to 0/off).
GMP 锟斤拷值锟斤拷源.
Example #1 gmp_setbit() example - 0 index
<?php
$a = gmp_init("2"); //
echo gmp_strval($a), ' -> 0b', gmp_strval($a, 2), "\n";
gmp_setbit($a, 0); // 0b10 now becomes 0b11
echo gmp_strval($a), ' -> 0b', gmp_strval($a, 2), "\n";
?>
锟斤拷锟斤拷锟斤拷锟教伙拷锟斤拷锟斤拷锟�
2 -> 0b10 3 -> 0b11
Example #2 gmp_setbit() example - 1 index
<?php
$a = gmp_init("0xfd");
echo gmp_strval($a), ' -> 0b', gmp_strval($a, 2), "\n";
gmp_setbit($a, 1); // index starts at 0
echo gmp_strval($a), ' -> 0b', gmp_strval($a, 2), "\n";
?>
锟斤拷锟斤拷锟斤拷锟教伙拷锟斤拷锟斤拷锟�
253 -> 0b11111101 255 -> 0b11111111
Example #3 gmp_setbit() example - clearing a bit
<?php
$a = gmp_init("0xff");
echo gmp_strval($a), ' -> 0b', gmp_strval($a, 2), "\n";
gmp_setbit($a, 0, false); // clear bit at index 0
echo gmp_strval($a), ' -> 0b', gmp_strval($a, 2), "\n";
?>
锟斤拷锟斤拷锟斤拷锟教伙拷锟斤拷锟斤拷锟�
255 -> 0b11111111 254 -> 0b11111110
Note:
Unlike most of the other GMP functions, gmp_setbit() must be called with a GMP resource that already exists (using gmp_init() for example). One will not be automatically created.