get file where class has been declared/required from

Question

how is it possible to get the file and line where a class has been declared from and/or required?

Answer 1

Use Reflections to figure out where a class was declared:

$reflector = new ReflectionClass('Foobar');
echo $reflector->getFileName();
echo $reflector->getStartLine();

Use inclued to figure out what was included where.