https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114436
--- Comment #4 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Lewis Hyatt <lhy...@gcc.gnu.org>: https://gcc.gnu.org/g:8c56d697b35d3d2ef802d068cad6b3bd026a2a1a commit r15-4331-g8c56d697b35d3d2ef802d068cad6b3bd026a2a1a Author: Lewis Hyatt <lhy...@gmail.com> Date: Fri Mar 22 15:42:43 2024 -0400 libcpp: Fix _Pragma("GCC system_header") [PR114436] _Pragma("GCC system_header") currently takes effect only partially. It does succeed in updating the line_map, so that checks like in_system_header_at() return correctly, but it does not update pfile->buffer->sysp. One result is that a subsequent #include does not set up the system header state properly for the newly included file, as pointed out in the PR. Fix by propagating the new system header state back to the buffer after processing the pragma. libcpp/ChangeLog: PR preprocessor/114436 * directives.cc (destringize_and_run): If the _Pragma changed the buffer system header state (e.g. because it was "GCC system_header"), propagate that change back to the actual buffer too. gcc/testsuite/ChangeLog: PR preprocessor/114436 * c-c++-common/cpp/pragma-system-header-1.h: New test. * c-c++-common/cpp/pragma-system-header-2.h: New test. * c-c++-common/cpp/pragma-system-header.c: New test.