Hey! I'm the author and maintainer of libgpiod. I'm currently getting ready to do a new major release. After giving some exposure to the release candidate, I noticed that when using clang, I can't link against the C++ bindings, while it works just fine in GCC.
The tree in question is here: https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git/log/ You can trigger the linking program by trying to build the C++ tests with clang like that: CC=clang CXX=clang++ ./autogen.sh --enable-bindings-cxx --enable-tests && make -j16 You'll get the following error: /usr/bin/ld: tests-chip.o:(.data+0x0): undefined reference to `typeinfo for gpiod::chip_closed' /usr/bin/ld: tests-line-request.o:(.data+0x0): undefined reference to `typeinfo for gpiod::request_released' /usr/bin/ld: .libs/gpiod-cxx-test: hidden symbol `_ZTIN5gpiod11chip_closedE' isn't defined /usr/bin/ld: final link failed: bad value The typoinfo is missing for exception types that should be visible to users of the library. The culprit is here: https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git/tree/bindings/cxx/gpiod.hpp#n26 I added the GPIOD_CXX_BUILD macro in order to not re-export the visible symbols if any user of the library would include the gpiod.hpp header. When the library is being built, the symbols are visible, when someone includes the header, the symbols are hidden. If I make the symbols unconditionally visible here, clang starts to work but I have no idea why and would like to avoid re-exporting the symbols if I can. I'm using the following version: Ubuntu clang version 15.0.6 Target: x86_64-pc-linux-gnu Thread model: posix InstalledDir: /usr/bin Host is: x86_64 GNU/Linux It's not like gcc links fine but then fails to obtain typeid - I can catch exceptions coming out from libgpiod just fine in external apps linked using gcc and see their type. Any hints? Thanks Bart _______________________________________________ linaro-toolchain mailing list -- linaro-toolchain@lists.linaro.org To unsubscribe send an email to linaro-toolchain-le...@lists.linaro.org
