On Wed, Nov 06, 2002 at 05:46:53PM +0100, Marc Olzheim wrote:
> ..
> if ((nd = parse_char_class(++nd)) == NULL) {
> ..
>
> Hmmm... is this legal ?
>
> http://www.eskimo.com/~scs/C-faq/q3.1.html seems to tell otherwise...In this particular case, the value of 'nd' is not *used* anywhere in the expression. The fact that 'nd' is *assigned to* is not influenced in any way by the change of its value. It is absolutely certain that the compiler will put the code calculating the value of the argument to parse_char_class() before the code actually invoking parse_char_class(), and that it will also place the code invoking parse_char_class() before the code which assigns the return value to 'nd'.. thus, it is absolutely certain that 'nd' will be assigned the correct value. Once again: the main reason why q3.1 is not relevant here is the fact that q3.1 deals with expressions where the value of 'nd' is used; here, the left side of the assignment does not 'use' the value, it *changes* it :) Hope that helps. G'luck, Peter -- Peter Pentchev [EMAIL PROTECTED] [EMAIL PROTECTED] PGP key: http://people.FreeBSD.org/~roam/roam.key.asc Key fingerprint FDBA FD79 C26F 3C51 C95E DF9E ED18 B68D 1619 4553 I've heard that this sentence is a rumor.
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