- define: documentation ( source)
<?php
define('DEFINED_AS_TRUE', true);
define('DEFINED_AS_FALSE', false);
echo 'Case A when not defined: ';
if ((!THIS_IS_NOT_DEFINED) || !defined('THIS_IS_NOT_DEFINED')) {
echo 'if is true';
}
else {
echo 'if is false';
}
echo "\n\n";
echo 'Case B when not defined: ';
if ((!defined('THIS_IS_NOT_DEFINED')) || (!THIS_IS_NOT_DEFINED)) {
echo 'if is true';
}
else {
echo 'if is false';
}
echo "\n\n";
echo 'Case A when defined as true: ';
if ((!DEFINED_AS_TRUE) || !defined('DEFINED_AS_TRUE')) {
echo 'if is true';
}
else {
echo 'if is false';
}
echo "\n\n";
echo 'Case B when defined as true: ';
if ((!defined('DEFINED_AS_TRUE')) || (!DEFINED_AS_TRUE)) {
echo 'if is true';
}
else {
echo 'if is false';
}
echo "\n\n";
echo 'Case A when defined as false: ';
if ((!DEFINED_AS_FALSE) || !defined('DEFINED_AS_FALSE')) {
echo 'if is true';
}
else {
echo 'if is false';
}
echo "\n\n";
echo 'Case B when defined as false: ';
if ((!defined('DEFINED_AS_FALSE')) || (!DEFINED_AS_FALSE)) {
echo 'if is true';
}
else {
echo 'if is false';
}