Why double Underbar in header files? Thank you..

[Just that]

Q: What does this mean ?
#define IT_MEANS__ //I see this in a lot of source files I downloaded

A:

 

[Victor Bazarov]

Q: What does this mean ?
#define IT_MEANS__ //I see this in a lot of source files I downloaded

A:

Double underscores create an illusion of importance or belonging to
some library code or give off some kind of "cool vibe" to those who
write them. They are doing so in violation of the Standard, though.
Subclause 17.4.3.1.2 reserves all names containing double underscores
to the implementation.

V