On Wed, 5 May 2021, David Laight via Libc-alpha wrote: > > __u64 can't be formatted with %llu on all architectures. That's not > > true for uint64_t, where you have to use %lu on some architectures to > > avoid compiler warnings (and technically undefined behavior). There are > > preprocessor macros to get the expected format specifiers, but they are > > clunky. I don't know if the problem applies to uint32_t. It does > > happen with size_t and ptrdiff_t on 32-bit targets (both vary between > > int and long). > > uint32_t can be 'randomly' either int or long on typical 32bit architectures. > The correct way to print it is with eg "xxx %5.4" PRI_u32 " yyy". C2X adds printf length modifiers such as "w32", so you can use a friendlier %w32u, for example. (Not yet implemented in glibc or in GCC's format checking.) -- Joseph S. Myers joseph@xxxxxxxxxxxxxxxx
