PHP crc32() Function
 Complete PHP String Reference
Definition and Usage
The crc32() function calculates a 32-bit CRC (cyclic redundancy checksum) for
a string.
This function can be used to validate data integrity.
Syntax
| Parameter |
Description |
| string |
Required. The string to be calculated |
Tips and Notes
Tip: To ensure that you get the correct string
representation from the crc32() function, you'll need to use the %u
formatter of the printf() or sprintf() function. If the %u formatter is not used, the result
may display
in incorrect and negative numbers.
Example 1
In this example we will print the result of crc32() with and without the "%u"
formatter (note that the result is equal):
<?php
$str = crc32("Hello world!");
echo 'Without %u: '.$str."<br />";
echo 'With %u: ';
printf("%u",$str);
?>
|
The output of the code above will be:
Without %u: 461707669
With %u: 461707669
|
Example 2
In this example we will print the result of crc32() with and without the "%u"
formatter (note that the result is not equal):
<?php
$str = crc32("Hello world.");
echo 'Without %u: '.$str."<br />";
echo 'With %u: ';
printf("%u",$str);
?>
|
The output of the code above will be:
Without %u: -1959132156
With %u: 2335835140
|
Complete PHP String Reference
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