Magic constants _ FILE _, _ LINE _ ,__ FUNCTION _ in php

_ FILE _: current FILE name _ LINE _: current row number _ FUNCTION _: current FUNCTION name _ CLASS _: current CLASS name _ METHOD _: the so-called magic constant of the current METHOD name, not a real constant, but a root

_ FILE _: current FILE name

_ LINE _: current row number

_ FUNCTION _: current FUNCTION name

_ CLASS _: current CLASS name

_ METHOD _: current METHOD name

The so-called magic constant is not a real constant, but a variable that gets a fixed value based on the occasion. the code is as follows:

2. Echo _ FILE __;
3. Echo'
   ';
4.  
5. Echo _ LINE __;
6. Echo'
   ';
7.  
8. Function funcTest ()
9. {
10. Echo _ FUNCTION __;
11. }
12. FuncTest ();
13. ?>