wp_rand( int $min = null, int $max = null ): int
Generates a random non-negative number.
Parameters
-
$min
int Optional -
Lower limit for the generated number.
Accepts positive integers or zero. Defaults to 0.Default:
null
-
$max
int Optional -
Upper limit for the generated number.
Accepts positive integers. Defaults to 4294967295.Default:
null
Return
int A random non-negative number between min and max.
Source
File: wp-includes/pluggable.php
.
View all references
function wp_rand( $min = null, $max = null ) {
global $rnd_value;
/*
* Some misconfigured 32-bit environments (Entropy PHP, for example)
* truncate integers larger than PHP_INT_MAX to PHP_INT_MAX rather than overflowing them to floats.
*/
$max_random_number = 3000000000 === 2147483647 ? (float) '4294967295' : 4294967295; // 4294967295 = 0xffffffff
if ( null === $min ) {
$min = 0;
}
if ( null === $max ) {
$max = $max_random_number;
}
// We only handle ints, floats are truncated to their integer value.
$min = (int) $min;
$max = (int) $max;
// Use PHP's CSPRNG, or a compatible method.
static $use_random_int_functionality = true;
if ( $use_random_int_functionality ) {
try {
// wp_rand() can accept arguments in either order, PHP cannot.
$_max = max( $min, $max );
$_min = min( $min, $max );
$val = random_int( $_min, $_max );
if ( false !== $val ) {
return absint( $val );
} else {
$use_random_int_functionality = false;
}
} catch ( Error $e ) {
$use_random_int_functionality = false;
} catch ( Exception $e ) {
$use_random_int_functionality = false;
}
}
/*
* Reset $rnd_value after 14 uses.
* 32 (md5) + 40 (sha1) + 40 (sha1) / 8 = 14 random numbers from $rnd_value.
*/
if ( strlen( $rnd_value ) < 8 ) {
if ( defined( 'WP_SETUP_CONFIG' ) ) {
static $seed = '';
} else {
$seed = get_transient( 'random_seed' );
}
$rnd_value = md5( uniqid( microtime() . mt_rand(), true ) . $seed );
$rnd_value .= sha1( $rnd_value );
$rnd_value .= sha1( $rnd_value . $seed );
$seed = md5( $seed . $rnd_value );
if ( ! defined( 'WP_SETUP_CONFIG' ) && ! defined( 'WP_INSTALLING' ) ) {
set_transient( 'random_seed', $seed );
}
}
// Take the first 8 digits for our value.
$value = substr( $rnd_value, 0, 8 );
// Strip the first eight, leaving the remainder for the next call to wp_rand().
$rnd_value = substr( $rnd_value, 8 );
$value = abs( hexdec( $value ) );
// Reduce the value to be within the min - max range.
$value = $min + ( $max - $min + 1 ) * $value / ( $max_random_number + 1 );
return abs( (int) $value );
}
Changelog
Version | Description |
---|---|
6.1.0 | Returns zero instead of a random number if both $min and $max are zero. |
4.4.0 | Uses PHP7 random_int() or the random_compat library if available. |
2.6.2 | Introduced. |
User Contributed Notes
You must log in before being able to contribute a note or feedback.
Get a random number between 1 and 100 (inclusive).
Generate a basic unique string appended with a random number
wp_rand( 0, 0 )
result in random integer instead of0
.Top ↑
Feedback
This was true for WP versions before 6.1. Since WP 6.1, wp_rand( 0, 0 ) now returns 0. — By Jason Coleman —