PHP 8.4.0 RC2 available for testing

gmp_cmp

(PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)

gmp_cmpCompare numbers

说明

gmp_cmp(GMP|int|string $num1, GMP|int|string $num2): int

Compares two numbers.

参数

num1

GMP 对象或 int ,或数字string

num2

GMP 对象或 int ,或数字string

返回值

Returns a positive value if a > b, zero if a = b and a negative value if a < b.

示例

示例 #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";
?>

以上示例会输出:

1 -1 0
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User Contributed Notes 1 note

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russell dot harper at springboardnetworks dot com
14 years ago
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";
}

?>
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