On Tuesday 2012-08-21 23:29, J. Bruce Fields wrote: >I've seen a couple examples recently where we've gotten this wrong. >Maybe something like this would help? Is there some better way? >(Approximation due to Jim Rees). > >+/* >+ * length of the decimal representation of an unsigned integer. Just an >+ * approximation, but it's right for types of size 1 to 36 bytes: >+ */ >+#define base10len(i) (sizeof(i) * 24 / 10 + 1)
gcc provides... "interesting" features at times. /* for unsigned "i"s */ #define base10len(i) ((const int[]){1,3,5,8,10,13,15,17,20}[i]) But enumerating it (using your ULONG_MAX_STR proposal) should be sufficient, since there is only a limited number of types that get e.g. sprintf'ed into a buffer. Something else tho, it seems some don't know that sizeof("") is already 1, and an extra \0 is often unneeded, like in: arch/um/drivers/net_user.c: char addr_buf[sizeof("255.255.255.255\0")]; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/