https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100462
Jakub Jelinek <jakub at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jakub at gcc dot gnu.org --- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> --- As documented - see https://gcc.gnu.org/onlinedocs/gcc/Precompiled-Headers.html - PCH is only tried if no C token is seen before the #include directive (comments and preprocessor directives like #if/#ifdef/#define/#undef are fine, but e.g. #pragma is not). So, is #include "gjs_pch.hh" the first thing in your sources?