* Alexander S. <alex0pla...@gmail.com> [2013-11-08 02:10:49 +0400]: > 2013/11/7 Szabolcs Nagy <n...@port70.net>: > > with a single pointer arg this assumes that all pointers have > > the same representation or that you create a separate version > > of pthread_create for every type used > Pthread_create doesn't need to know anything about the type of the > pointer! In fact, nobody except the typechecker needs to.
if different pointers have different representations then the caller needs to know that at runtime to pass the argument to the callback > Runtime information is only needed if you are going to actually > introspect that arbitrary number of args. If you are going to plop > them back onto the stack, the only thing you need to know is a total > size, which can be calculated in compile time. that's not how the function call abi works and what you describe can be done now in c without the syntax: allocate a char array on the stack serialize everything into it, and pass the pointer and size you don't get typesafety, but that cannot be done in general accross a serialize/deserialize step, you could only type check a few special case of that at best.. by making things more complicated > expansion C varargs undergo. But, I suppose, asking that all arguments > be either floating-point or pointer-size isn't asking too much. It is > doable. the size is not all there are function pointers, structures with alignment requirements, paddings and bitfields, some implementations support more than three different floating-point types.. in the end you either have runtime type information to be able to unpack the arguments and construct calls with them or you have what c has now
