On 27/03/2025 10:08 pm, Fred Wright wrote:
On Thu, 27 Mar 2025, Chris Jones via macports-dev wrote:
On 27/03/2025 12:35 pm, René J.V. Bertin wrote:
Hi,
I've been experimenting with libc++ 17 which is a prerequisite to
using GCC13+ with libc++ instead of libstdc++ .
I kept the static legacy-support library linking (may have had to,
can't remember that) and just now realise that all the functions from
that archive (or at least the from the modules that get pulled in)
are exported by libc++ .
That's probably a bad idea. ISTR a post from Ken regarding compiler
uses of legacy-support being statically linked, but that was to avoid
circular dependencies. There may have been some circular dependency
issues at one time, due to legacy-support's being constrained to
MacPorts compilers in some cases by the cxx_stdlib setting, but I fixed
that over a year ago. Nowadays, legacy-support is completely dependency-
free except for needing apple-gcc42 to build on 10.4, and static linking
should be avoided as much as possible.
which libc++ in particular are you talking about here ? For sure the
system libc++ will never export anything from legacysupport.
I presume that "libc++ instead of libstdc++" means that it's not
referring to a system libc++.
The libc++ versions as provided by the MacPorts clang ports might well
include some symbols from legacysupport, as its use is required to
build these compilers on old systems. I don't thunk hiding these
symbols in these versions is at all a good idea.
A proper compiler should make a proper distinction between host
requirements and target requirements, though I wouldn't put it past GCC
to get that wrong. What the compiler needs to build and run should be
completely independent from what its target needs.
If libc++ is statically linked with legacy-support, then it will of course
contain any legacy-support symbols that it references. If it's
dynamically linked, then it won't unless it's been explicitly configured
to do so.
They intentionally link statically.
https://github.com/macports/macports-ports/blob/master/lang/llvm-20/Portfile#L15
Fred Wright
