Saagar Jha > On Sep 24, 2019, at 01:56, Christopher Jones <jon...@hep.phy.cam.ac.uk> wrote: > > Hi, > > Note the error is not specific to gcc. Macports clang has the same problem. > > > clang++-mp-8.0 -O3 ./main.cpp > In file included from ./main.cpp:1: > In file included from > /opt/local/libexec/llvm-8.0/bin/../include/c++/v1/iostream:38: > In file included from > /opt/local/libexec/llvm-8.0/bin/../include/c++/v1/ios:215: > In file included from > /opt/local/libexec/llvm-8.0/bin/../include/c++/v1/iosfwd:96: > /opt/local/libexec/llvm-8.0/bin/../include/c++/v1/wchar.h:119:15: fatal > error: 'wchar.h' file not found > #include_next <wchar.h> > ^~~~~~~~~ > 1 error generated. > > The issue is both macports clang and gcc rely (by default) on /usr/include > being present, and this is no longer present by default with Xcode 11, and > even if you previously had it was likely wiped out with the last update. > > Note, with 10.14 at least (*) you can add back /usr/include by following the > instructions in > > https://apple.stackexchange.com/questions/337940/why-is-usr-include-missing-i-have-xcode-and-command-line-tools-installed-moja > > <https://apple.stackexchange.com/questions/337940/why-is-usr-include-missing-i-have-xcode-and-command-line-tools-installed-moja> > > or, as you say below, explicitly giving the include path in some way, such as > the suggestion below. > > cheers Chris > > (*) The package to add back /usr/include currently does not exist in 10.15 > beta, so unless it reappears come final release this is going to be more of a > problem there….
This package is not going to be coming back: https://developer.apple.com/documentation/xcode_release_notes/xcode_10_release_notes#3035623 <https://developer.apple.com/documentation/xcode_release_notes/xcode_10_release_notes#3035623> >> On 24 Sep 2019, at 7:09 am, Joshua Root <j...@macports.org >> <mailto:j...@macports.org>> wrote: >> >> On 2019-9-24 15:31 , Mihir Luthra wrote: >>> Hi, >>> >>> After the xcode update, there have been many question on stackoverflow >>> regarding gcc and g++ linking fails. Any ideas on what can be done? >>> >>> https://stackoverflow.com/questions/58072318/cannot-link-any-c-program-with-gcc-on-mac-mojave >>> >>> <https://stackoverflow.com/questions/58072318/cannot-link-any-c-program-with-gcc-on-mac-mojave> >>> >>> https://stackoverflow.com/questions/58073301/linker-error-when-trying-to-use-lzma-in-boostiostreams-from-macports >>> >>> https://stackoverflow.com/questions/58071057/macports-g-fails-to-find-headers-after-recent-xcode-update >>> >>> Mihir >> >> Does passing -isysroot`xcrun --show-sdk-path` to the compiler not work? >> >> While that should make it find headers again, I don't know how many bugs >> it will uncover. I'm not sure how we would make this work out of the box >> for everyone, since AIUI, gcc needs to apply different fixups to the >> system headers depending on the SDK version and does so at build time. >> So Apple taking away not only the SDK corresponding to the current OS >> version but also /usr/include is quite problematic. We can ship a gcc >> supporting the 10.14 SDK or the 10.15 SDK, but not both. >> >> Rebuilding gcc from source would also work. >> >> - Josh >