On 2019-11-15 20:35, Brian Inglis wrote: > On 2019-11-15 15:25, Arthur Norman wrote: >>> I notice that you are not independently compiling your source files and >>> have no >>> include guard in t.h. >>> Could I suggest that you add the include guard to t.h and retest. >>> If you still have an issue, try independently compiling your source files, >>> then >>> linking them as a separate step, to see if that works. >>> You could also test reproducing the issue on another gcc platform, under a >>> Unix >>> VM, or a WSL Linux distro. >> >> I attach a versiuon of the test with an include guard and with t1.cpp and >> t2.cpp >> compiled in separate invocations of g++ - I still see the multiple >> definition. >> >> ${1:-g++} -std=c++17 -I. -c t1.cpp >> ${1:-g++} -std=c++17 -I. -c t2.cpp >> ${1:-g++} -std=c++17 t1.o t2.o -o t >> /usr/lib/gcc/x86_64-pc-cygwin/8.3.0/../../../../x86_64-pc-cygwin/bin/ld: >> t2.o:t2.cpp:(.text+0x86): multiple definition of `TLS init function for >> Data::valref'; t1.o:t1.cpp:(.text+0x4a): first defined here >> collect2: error: ld returned 1 exit status >> ./t >> >> As per my original posting before enquiring here I had tried on a 64-bit >> ubuntu >> machine, on a Macbook (where it is clang not g++, but I invoke the compiler >> as >> g++) and on a Raspberry pi. > > Sorry missed that. > >> The original code I had pain with was with include guards and all files >> compiled >> independently via make - the test casee I submitted had perhaps tried to >> hard to >> shorten and simplify. >> >> I also tried both 32 and 64-bit mingw compilers under cygwin - making that >> easier is why the test script goes ${1:-g++} so I can override the compiler >> selection to be x86_64-w64-mingw32-g++ or the i686 variant. Those both show >> the >> multiple definition problem. > > That points to a common problem with the loader generating Windows PEs: it is > possible that is a Windows limitation. > As ld is part of binutils, you might want to try searching and posting on that > mailing list, conveniently located just next door: > > https://sourceware.org/binutils/ > http://sourceware.org/ml/binutils/ > http://lists.gnu.org/archive/html/bug-binutils/ > > before looking further at gcc.
OTOH: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64697#c20 > Please emphasize clearly that this works successfully with ELF executables on > Unix platforms, and list those; and ld fails only with Windows (PE) > executables > using Cygwin and Mingw 32/64 tool chains, and list those; and include the test > code, commands and results on each platform, to clearly demonstrate the issue. > Use a specific subject to get appropriate attention and a relevant response > e.g. > "ld fails only for Windows PE with multiple definition of TLS init function". -- Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada This email may be disturbing to some readers as it contains too much technical detail. Reader discretion is advised. -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple