> So either return the whole struct as values or, alternatively - and this is the way most library functions do it - call the function with a pointer to an empt

> So either return the whole struct as values or, alternatively - and this is the way most library functions do it - call the function with a pointer to an empty struct which the function then fills. Mind you, under the hood all your structs will be returned through pointers to caller-allocated memory, unless it can fit into 8 bytes. “To return a user-defined type by value in RAX, it must have a length of 1, 2, 4, 8, 16, 32, or 64 bits. [...] Otherwise, the caller assumes the responsibility of allocating memory and passing a pointer for the return value as the first argument.” https://docs.microsoft.com/en-us/cpp/build/x64-calling-convention?view=vs-2019#return-values https://docs.microsoft.com/en-us/cpp/build/x64-calling-conve...