Comment by jstimpfle
2 years ago
SIZE_MAX is the largest possible value of type size_t. size_t is defined as an unsigned type that is big enough to represent the size of the largest possible object (which basically means the size of the virtual address space i.e. 2^32 on a 32-bit system and usually 2^48 on a 64-bit system, which is being addressed with an uint64_t).
None of that is relevant since you're extremely unlikely to hit either limit by accident. If you really want, you can hit 32-bit limit if you're doing things that snprintf really shouldn't be used for, and likewise you can hit size_t limit if you're on a 32-bit system and joining multiple large strings.
Yes, my point is just that since all the "strn" C string-handling functions in the standard library use a size_t for the size if you've got more than INT_MAX characters there's not necessarily any problem. INT_MAX is pretty much always going to be lower than SIZE_MAX, even on 32-bit systems since the former is signed and the latter isn't. You just call snprintf or whatnot as usual. If you manage to have more than SIZE_MAX characters, then you have a problem. Libc probably can't solve it for you though, since SIZE_MAX has to be large enough to cover any allocation so you have some sort of segmented architecture that the C standard library isn't expecting.