On Thu, 21 Jun 2018 00:28:27 +0200, Jakub Wilk wrote: > POSIX actually requires that CHAR_BIT is exactly 8. > > It seems that at least some parts of the man page you wrote is based on > the incorrect assumption than CHAR_BIT can be greater than 8 on POSIX > systems. Thanks for the reply. There are 2 threads in the man page: * Documentation of the fact that Linux/POSIX define a byte to be 8 bits, which I took to imply that CHAR_BIT on POSIX is indeed supposed to be 8. * Documentation of the fact that in general, there's a discrepancy in definitions that needs to be taken into acount when dealing with the portability of both programs and their data. Of course, perhaps the man page should be a little more explicit in documenting that POSIX conformance demands CHAR_BIT be 8 (e.g., by quoting the constraints placed on <limits.h>); at one point, I did have a code example demonstrating a test for POSIX compatibility as a means by which to imply an 8-bit char, but I removed it because I thought it was superfluous. That being said, POSIX compatibility is not the same as POSIX-like; to be extra careful, it's probably better not to rely on a resemblance to POSIX, but instead to use testing that is more direct, which is why the examples don't rely on just POSIX for determining CHAR_BIT (after all, you can just test CHAR_BIT itself). More to the point, it is not intended to help programmers who are targeting solely POSIX. Is there something in particular that is outright incorrect? Sincerely, Michael Witten -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
