wp_rand() WP 2.6.2

Generates a random number between the specified min and max.

No Hooks.

Return

Int. A random number between min and max

Usage

wp_rand( $min, $max );

$min(int)

Lower limit for the generated number

$max(int)

Upper limit for the generated number

Examples

#1 Basic usage

echo wp_rand( 99, 99999 ); // 19899, 85724, 77130, 51575
echo wp_rand( 1.5, 5.5 );  // 5, 1, 3, 4
echo wp_rand( 5, 4 );      // always 5

Notes

• Global. String. $rnd_value

Changelog

Code of wp_rand() wp rand ^{WP 5.7.1}

<?php
function wp_rand( $min = 0, $max = 0 ) {
	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

	// 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 {
			$_max = ( 0 != $max ) ? $max : $max_random_number;
			// 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.
	if ( 0 != $max ) {
		$value = $min + ( $max - $min + 1 ) * $value / ( $max_random_number + 1 );
	}

	return abs( (int) $value );
}

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