On Wed, Jan 20, 2021 at 10:25:56PM +0000, David Laight wrote: > I also wonder if pread/pwrite with offset == 0 should be valid > on things where the offset makes no sense. > > I'm rather surprised the offset isn't just silently ignored > for devices where seeking is non-sensical. > You might want to error it for mag tapes, but not pipes, > ttys, sockets etc. > > I really can't remember what SYSV, Solaris or NetBSD do.
... nor can you be arsed to RTFPOSIX. Why am I not surprised? In https://pubs.opengroup.org/onlinepubs/9699919799/functions/write.html (located by arcane action known as googling for pwrite POSIX): ============================== The pwrite() function shall fail if: [EINVAL] The file is a regular file or block special file, and the offset argument is negative. The file offset shall remain unchanged. [ESPIPE] The file is incapable of seeking. ==============================
