I have encounter this macro: __VA_ARGS__ - variadic macro in a document. It is used to expand the triple dots in macro definition (like define SMF(...) fprintf(stdout, __VA_ARGS__), but when I wanted to find its implementation (How does it expand all agruments given - just its implementation) - I have tried
sudo cd /; grep -r '#define __VA_ARGS__ (mentioned #define, so it doesnt emit that macro just in 'use' but rather its definition). It was searching quit long, but it only gave I hadnt have permission on some directories (e. g. sys/kernel/debug/block/loop17/hctx0/cpu3/read_rq_list - even when trigered with sudo - dont know why, but thats another story). Still didnt tell where to look (in what file). So if it didnt find that macro from root dir (and recursively look in others), where should I look then?
PS: I know that when macro starts with double underscore, it is either system macro or compilator (gcc) macro, but when I did similar with gcc (grep __VA_ARGS__ via man gcc | grep ...), even there no success.