…Can such a view be clarified further according to available information?
"__" prefix added to internal macros;
…
Would you get into the mood to reconsider the usage of leading underscores
any more for selected identifiers?
https://wiki.sei.cmu.edu/confluence/display/c/DCL37-C.+Do+not+declare+or+define+a+reserved+identifier
The mentioned URL doesn't cover the special cases like the kernels of the
operating systems or other quite low level code.
Regards,
Markus