How to escape double underscore and single underscore in rg.

[jianhe-fun]

I do tried.

rg '[[__FLT_DIG__]]' .
rg \_\_FLT_DIG\_\_ .
rg "__FLT_DIG__" .
rg '__FLT_DIG__' .

But How do I capture content contains __FLT_DIG__
for example, the following line do match the pattern.
#define FLT_DIG __FLT_DIG__

[BurntSushi]

This is almost certainly an instance of the XY problem. Namely, underscores never need to be escaped because they are not meta characters:

$ echo '#define FLT_DIG __FLT_DIG__' | rg __FLT_DIG__
#define FLT_DIG __FLT_DIG__

So if rg __FLT_DIG__ isn't showing the matches you expect, then it's almost certainly because of some other problem. You'll need to either provide a complete reproduction, and/or take a look at the --debug output. Remember, as the very first lines of the ripgrep docs state, ripgrep will by default ignore things matching your gitignore, hidden files and binary files.