PHP5.3 + new magic variable

After reading PHP5.3 +'s new Magic variables, they are still very common: [common PHP magic variables] _ NAMESPACE _ current NAMESPACE _ DIR _ the directory where the current PHP script is located is equivalent to & amp; nbsp; dirname (_ FILE __)

Read itPHP5.3 + new magic variable, Or very common: [common PHP magic variables]
_ NAMESPACE _ current NAMESPACE
_ DIR _ the directory where the current PHP script is located is equivalent to dirname (_ FILE __)
This makes it much easier to introduce new files in development:

Require _ DIR _. '/../vendor/autoload. php ';