在 2023/12/1 16:19, Eli Zaretskii via Gcc 写道:
>> As far as I understand it, mingw doesn't have fork and doesn't declare
>> it in <unistd.h>, so it's not clear to me how this has ever worked.  I
>> would expect a linker failure.  Maybe that doesn't happen because the
>> object containing a reference to fork is only ever pulled in if the
>> application calls the intercepted fork, which doesn't happen on mingw.

That's correct. No program has been calling `fork()` in any way.


>> What's the best way to fix this?  I expect it's going to impact other
>> targets (perhaps for different functions) because all of
>> libgcov-interface.c is built unconditionally.  I don't think we run
>> configure for the target, so we can't simply check for a definition of
>> the HAVE_FORK macro.
> 
> I'm not familiar with this code, so apologies in advance if what I
> suggest below makes no sense.
> 
> If the code which calls 'fork' is never expected to be called in the
> MinGW build, then one way of handling this is to define a version of
> 'fork' that always fails, conditioned by a suitable #ifdef, so that
> its declaration and definition are visible when this file is compiled.

Makes sense. The target-specific macro `_WIN32` serves that purpose.

However `fork()` doesn't actually exist there, and linking should indeed fail. Maybe `__gcov_fork()` 
shouldn't be defined at all.


-- 
Best regards,
LIU Hao