Set the type of variable var to type.
Possibles values of type are:
"boolean" (or, since PHP 4.2.0, "bool")
"integer" (or, since PHP 4.2.0, "int")
"float" (only possible since PHP 4.2.0, for older versions use the deprecated variant "double")
"string"
"array"
"object"
"null" (since PHP 4.2.0)
Returns TRUE on success or FALSE on failure.
See also gettype(), type-casting and type-juggling.