On 5 January 2015 at 11:21, Daniel Murphy via Digitalmars-d <digitalmars-d@puremagic.com> wrote: > "Iain Buclaw via Digitalmars-d" wrote in message > news:mailman.4143.1420452193.9932.digitalmar...@puremagic.com... > >> That depends on how we agree to go forward with this. From memory, we >> each do / did things differently. >> >> I have no doubt that the way I've done it is a kludge at best, but >> I'll explain it anyway. >> >> GDC *always* uses the real va_list type, our type-strict backend >> demands at least that from us. So when it comes down to the problem >> of passing around va_list when it's a static array (extern C expects a >> ref), I rely on people using core.vararg/gcc.builtins to get the >> proper __builtin_va_list before importing modules such as >> core.stdc.stdio (printf and friends) - as these declarations are then >> rewritten by the compiler from: >> >> int vprintf(__builtin_va_list[1] va, in char* fmt, ...) >> >> to: >> >> int vprintf(ref __builtin_va_list[1] va, in char* fmt, ...) >> >> >> This is an *esper* workaround, and ideally, I shouldn't be doing this... > > > I just read the discussion in > https://github.com/D-Programming-Language/dmd/pull/3568 and I think I > finally get it, lol. > > AIUI your solution won't work for user C++ functions that take va_list, > because either type or mangling will be correct, but never both. Is that > correct? Can gdc compile the tests in 3568? >
That is correct for user code, but not druntime C bindings. GDC can compile the test in 3568 thanks to the GCC backend providing the va_list struct a name (__va_list_tag). However it for sure cannot run the program though. Only body-less declarations in core.stdc.* are rewritten to ref va_list.
