On 24/03/2026 3:02 pm, Sergey Fedorov wrote:
To be clear: on powerpc (and by default outside of MacPorts generally)
gcc uses libstdc++, and that works fine.
MacPorts uses libc++ with gcc on archs other than powerpc, which is what
fails. It is not a fault of gcc, it is a fault of libc++ being outdated.
This should work fine on 10.5 out of the box.
Wrong. By default building c++ with gcc will always link against
libstdc++, not libc++ . MacPorts GCC version have the option to use
libc++, but how well this works in practice is pretty flaky.
This is why we don't in general allow gcc as a fallback compiler for C++
builds, as doing so would result in binaries ABI incompatble with other
binaries built with clang++. Forcing the use of gcc for this, with
configure.compiler=macports-gcc-15 is very much in-advised on any
platform where libc++ is the default runtime (i.e. all but the very
oldest ancient OSes).
Chris
