On Wed, 9 Oct 2019 at 04:49, Klaus Doldinger wrote: > > Hi all, > > following is an example regarding the generation of guards for the > static m in template X. I didn't check the implementation, but according to the documentation, -fno-threadsafe-statics only affects local static, so it's unsurprising that it doesn't have any effect on a static member variable. For the local static variable, GCC and Clang still emit the guard variable with -fno-threadsafe-statics but they do not emit the code to use that variable (there are no calls to __cxa_guard_acquire or __cxa_guard_release). I believe the guard variable stills gets be emitted for ABI reasons, because another translation unit compiled without -fno-threadsafe-statics might be expecting it to exist.
