https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108331
Bug ID: 108331 Summary: ABI break of std::__c_file and std::fstream for win32 thread model of GCC for windows Product: gcc Version: 13.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: libstdc++ Assignee: unassigned at gcc dot gnu.org Reporter: unlvsur at live dot com Target Milestone: --- The recent win32 thread model changes cause abi break of std::fstream due to layout silently change. I do not understand why you need a mutex for std::fstream. Now win32, posix and mcf thread model they cause abi issues for this due to that lock. Can we unify the abi for windows here?