On Mon, Mar 04, 2024 at 04:09:26PM +0100, Alejandro Colomar wrote: > Depending on the width of those types, the sum may be performed as > 'loff_t' if `sizeof(loff_t) > sizeof(size_t)`, or as 'size_t' if > `sizeof(loff_t) <= sizeof(size_t)`. Since 'loff_t' is a 64-bit type, > but 'size_t' can be either 32-bit or 64-bit, the former is possible. > > In those platforms in which loff_t is wider, the addends are promoted to > 'loff_t' before the sum. And a sum of positive signed values can never > be negative. If the sum overflows (and the program above triggers > such an overflow), the behavior is undefined. Linux is compiled with -fwrapv so it is defined.
