funny looking comments - c++

Question

when i read through source files of opensource projects i often come across some weird phrases in the comments

/*       
@brief ......  
@usage.....  
@remarks....  
@par....  
*/

questions
1.What are they?(were not mentioned when i was learning c++)
2.Do they have any documentation(where)

Answer 1

They are just comments and as such have no special meaning in C++. They are probably to allow a documentation generator (For example Doxygen) to extract the data from the comments.

Answer 2

Those are for some flavour of automatic documentation generator. Another program runs through the code looking for comments of like you see there. The @... keywords identify how the documentation should be laid out, and that program generates pretty HTML or printed documentation directly from the source code. It's a way to keep the docs up-to-date with the code more easily.