(PHP 4 >= 4.0.4, PHP 5)
gmp_cmp — Compare numbers
$a
, resource $b
)Compares two numbers.
a
可以是一个 GMP 数据 resouce，或一个可以转换为数值的字符串。
b
可以是一个 GMP 数据 resouce，或一个可以转换为数值的字符串。
Returns a positive value if a > b, zero if a = b and a negative value if a < b.
Example #1 gmp_cmp() example
<?php
$cmp1 = gmp_cmp("1234", "1000"); // greater than
$cmp2 = gmp_cmp("1000", "1234"); // less than
$cmp3 = gmp_cmp("1234", "1234"); // equal to
echo "$cmp1 $cmp2 $cmp3\n";
?>
以上例程会输出：
1 -1 0
russell dot harper at springboardnetworks dot com (2010-07-28 13:43:54)
I've encountered a memory leak in gmp_cmp if a literal string is used as the second value inside of loops. A workaround is to initialize first, then use the variable. I wasn't able to generate a minimum code sample, it's something more complicated, but I was able to fix it as follows:
<?php
$x = gmp_init(strval(mt_rand()));
// Depending on surrounding code, may have leaks
while (true)
{
if (!gmp_cmp($x, '1'))
print 'one'."\n";
}
// Usually doesn't have leaks
$one = gmp_init('1');
while (true)
{
if (!gmp_cmp($x, $one))
print 'one'."\n";
}
?>