Variadic arguments

Functions that take variadic arguments can be registered with the engine, though the function has to be implemented with the generic calling convention.

When a function is registered as taking variadic arguments, the compiler will push an extra hidden argument on the stack holding the number of arguments passed to the function. This is used by the asIScriptGeneric interface to know how many arguments there are. The application doesn't have to explicitly read this hidden argument, but can just use the GetArgCount method normally. The argument type for all the arguments passed to the variadic will be the same, which is the type that the application registered for it.

A common option for the argument is const ?&in ... for taking a list of variable argument types as input, or ?&out ... for taking a list of output arguments of variable types. But it is perfectly fine to specify a single type, e.g. int ..., if that is all that is required.

r = engine->RegisterGlobalFunction("string format(const string&in fmt, const ?&in ...)", asFUNCTION(StringFormat), asCALL_GENERIC); assert(r >= 0);
r = engine->RegisterGlobalFunction("uint scan(const string&in str, ?&out ...)", asFUNCTION(StringScan), asCALL_GENERIC); assert(r >= 0);

See also

The implementation of format and scan in the string add-on