On Mar 22 2013, Tobias Burnus wrote:
The front end and the backend are both compiled with the same compiler
and in the same binary. Even without bootstrapping, trying to compile
them with different compilers, will require some heavy editing of
makefiles. Thus, it seems to be extremely unlikely that different
compilers have ever been used. The change from C99's bool to C++'s bool
occurred for the whole compiler. Before 4.7 the default was to compile
GCC with C (though it had been modified to be also compilable with C++);
in 4.7, the default compiler was C++ but C was still supported. And
since GCC 4.8 C++ features are used, which makes GCC only compilable
with C++. Actually, the FE itself so far uses nearly no C++ features, it
is the middle end which used them (which 'leak' to the front end via
some helper macros/functions).
Ah. I misunderstood what people said. Yes, if C++ mode is used for
the whole compiler, everything is fine. And it remains so even if
the code plays fairly clever games. I don't know if there are any
compilers that generate incompatible bool types in C and C++ modes,
but it wouldn't surprise me if there were.
In terms of the discussion, "bool" is used for quite some time in
gfortran (the frontend) and libgfortran. When GCC was compiled with C,
that was C99's _Bool. Since the compiler is compiled as C++, it is C++'s
"bool". Thus, C/C++'s bool are never mixed.
Then there is no problem. Sorry about the red herring - I misunderstood
what people said. Unfortunately, from personal experience, the majority
of people even on WG14 and WG21 do not understand the incompatibilities,
which is why I posted.
Regards,
Nick Maclaren.
