pub unsafe trait VaArgSafe: Sealed { }🔬This is a nightly-only experimental API. (
c_variadic #44930)Expand description
Types that are valid to read using VaListImpl::arg.
§Safety
The standard library implements this trait for primitive types that are expected to have a variable argument application-binary interface (ABI) on all platforms.
When C passes variable arguments, integers smaller than c_int and floats smaller
than c_double are implicitly promoted to c_int and c_double respectively.
Implementing this trait for types that are subject to this promotion rule is invalid.