https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95604
--- Comment #3 from H.J. Lu <hjl.tools at gmail dot com> --- (In reply to Matthias Klose from comment #2) > Really? The documentation states: > > The macro "__CET__" is defined when -fcf-protection is used. > > so it's a preprocessor option as well? __CET__ check isn't needed to enable CET in C/C++. __CET__ is needed to add CET support to assembly codes. If there are mixed source codes, -fcf-protection should be used for compilation.