gmp_cmp
(PHP 4 >= 4.0.4, PHP 5, PHP 7)
gmp_cmp — Compare numbers
说明
$a
, GMP $b
)Compares two numbers.
参数
-
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。
返回值
Returns a positive value if a > b, zero if a = b and a negative value if a < b.
范例
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
用户评论:
[#1] 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";
}
?>