On Sat, 12 Feb 2011 07:47:38 +0100 Albert ARIBAUD albert.aribaud@free.fr wrote:
Le 12/02/2011 00:11, Kim Phillips a écrit :
I'd have done it without magic nor comments as
U_BOOT_VERSION[sizeof("U-Boot ") + 1]
or even
U_BOOT_VERSION[strlen("U-Boot ")]
The second one calls strlen() at run-time, plus it allocates the "U-Boot " string for no justifiable reason -- assuming the first one can be compile-time evaluated by the compiler, of course.
no, the compiler evaluates the strlen at compile time and eliminates the need to allocate the "U-Boot " string in both cases.
that's not to say that there aren't a couple of gaffes above: the sizeof needs a - 1 instead of a + 1 (because it includes the trailing '\0'), and both expressions need to be prepended with an '&'. So, we have something like:
&U_BOOT_VERSION[sizeof("U-Boot ") - 1]
or
&U_BOOT_VERSION[strlen("U-Boot ")]
Kim