Where can I find more information about D_GLIBCXX_DEBUG and DNDEBUG flags?

Question

I am trying to understand D_GLIBCXX_DEBUG and DNDEBUG flags.

But I can't find information about them.

Can anyone explain what they do? and where can I read more about them?

Answer 1

Both use -D which defines the macro given after the D.

When NDEBUG is defined, assert does not check its argument.

When _GLIBCXX_DEBUG is defined, it activates debug mode in libstdc++ (causing libstdc++ to perform checks on various operations).