bugs. If you discover a constant mysteriously evaluating to zero, check that the constant
has been defined.
<?
/*
* Database variables
/
define("DATABASE_HOST", "localhost");
define("DATABASE_USER", "httpd");
define("DATABASE_PASSWORD", "");
define("DATABASE_NAME", "freetrade");
print("Connecting to ". DATABASE_HOST. "
\n");
?>
boolean defined(string constantname)
The defined function returns TRUE if a constant exists, FALSE otherwise.
<?
define("THERMOSTAT","72 degrees");
if(defined("THERMOSTAT"))
{
print("THERMOSTAT is ". THERMOSTAT);
}
?>
double doubleval(expression)
The doubleval function returns its argument as a double. Chapter 2 discusses
converting between data types. Related functions are strval and intval. It is an error to
pass an array or object to doubleval.
<?
$myNumber = "13.1cm";
print(doubleval($myNumber));
?>
empty
This function is an alias for isset.
string gettype(expression)