Re: [linux-pm] [PATCH] ACPI: replace strlen("string") withsizeof("string") -1

From: Alan Stern
Date: Mon Aug 06 2012 - 10:36:56 EST


On Mon, 6 Aug 2012, Pavel Machek wrote:

> On Thu 2012-07-26 21:39:38, Len Brown wrote:
> > ...both give the number of chars in the string
> > without the '\0', as strncmp() wants,
> > but sizeof() is compile-time.
>
> What about introducing something like streq() to do this
> automatically? This is ugly....
>
> #define streq(a, b) ... if (_buildin_constant(b)) ...
>
> ?
>
> > - if (!strncmp(val, "enable", strlen("enable"))) {
> > + if (!strncmp(val, "enable", sizeof("enable") - 1)) {

While you're at it, there's no point using strncmp when you know the
length of one of the strings beforehand. Just use memcmp, and don't
subtract 1 from the sizeof value.

Alan Stern

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