Hi Willy! On 2023-08-29 08:28:27+0200, Willy Tarreau wrote: > On Sun, Aug 27, 2023 at 10:00:15AM +0200, Thomas Weißschuh wrote: > > This allows nolic to work with `-nostdinc` avoiding any reliance on > > system headers. > > > > The implementation has been lifted from musl libc 1.2.4. > > There is already an implementation of stdarg.h in include/linux/stdarg.h > > but that is GPL licensed and therefore not suitable for nolibc. > > I'm a bit confused because for me, stdarg was normally provided by the > compiler, but I could be mistaken. It's just that it reminds me not so > old memories. Therefore maybe we just need to include or define > "something" to use it. It is indeed provided by the compiler. I could not find anybody doing this differently. Using builtins seems to me to be the normal way to expose compiler implementation specifics. > > +#ifndef _NOLIBC_STDARG_H > > +#define _NOLIBC_STDARG_H > > + > > +typedef __builtin_va_list va_list; > > +#define va_start(v, l) __builtin_va_start(v, l) > > +#define va_end(v) __builtin_va_end(v) > > +#define va_arg(v, l) __builtin_va_arg(v, l) > > +#define va_copy(d, s) __builtin_va_copy(d, s) > > + > > +#endif /* _NOLIBC_STDARG_H */ > > Also, regarding the doubt above, I really think these should be guarded > (maybe just use va_start as a hint), because the risk that they come > from libc headers or maybe from the compiler via another include path > is non-negligible. I can add a guard. It would only protect against the case where the other stdarg.h is loaded first, not if ours is loaded first. Although these symbols should always only come from some <stdarg.h> and within a single CU this should always end up being the same file. Thomas
