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Define and Use a Constant

Defines a PHP constant only when it is not already defined, then uses it in a small configuration calculation.

Purpose

Defines a PHP constant only when it is not already defined, then uses it in a small configuration calculation.

Snippet details

ContextUtilityLevelProductionCopy-and-paste statusMarked safe after review.

Categories

  • Forms and Validation

Code

<?php

/*
 * Copyright (c) 2026 Jeffery L. Paris <jparis@phpog.com>.
 * Free for personal and internal use. Paid project use requires visible credit
 * to Jeffery L. Paris. Corporate use requires a paid license fee unless a
 * separate written license states otherwise.
 */

/**
 * Define and Use a Constant.
 *
 * Purpose:
 * Shows how to define a constant once, check for it with defined(), and use it
 * as a stable application setting.
 *
 * @param int $active_ships Number of active ships currently shown.
 * @return array Constant value and capacity status.
 */
function ogSnippetDefineAndUseAConstant(int $active_ships): array {
	if (defined('OG_SNIPPET_FLEET_LIMIT') === false) {
		define('OG_SNIPPET_FLEET_LIMIT', 12);
	}

	if ($active_ships < 0) {
		return array(
			'success' => false,
			'fleet_limit' => OG_SNIPPET_FLEET_LIMIT,
			'message' => 'Active ship count cannot be negative.'
		);
	}

	$slots_remaining = OG_SNIPPET_FLEET_LIMIT - $active_ships;

	if ($slots_remaining < 0) {
		$slots_remaining = 0;
	}

	return array(
		'success' => true,
		'fleet_limit' => OG_SNIPPET_FLEET_LIMIT,
		'active_ships' => $active_ships,
		'slots_remaining' => $slots_remaining,
		'at_capacity' => $active_ships >= OG_SNIPPET_FLEET_LIMIT
	);
}

/*
$result = ogSnippetDefineAndUseAConstant(9);
print_r($result);
*/