Messages in this thread | | | From | Andreas Schwab <> | Subject | Re: [for-next][PATCH 23/24] string.h: Add strncmp_prefix() helper macro | Date | Fri, 21 Dec 2018 21:58:32 +0100 |
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On Dez 21 2018, Steven Rostedt <rostedt@goodmis.org> wrote:
> On Fri, 21 Dec 2018 12:46:47 -0800 > Joe Perches <joe@perches.com> wrote: > >> > + * @str: The string to test >> > + * @prefix: The string to see if @str starts with >> > + * >> > + * A common way to test a prefix of a string is to do: >> > + * strncmp(str, prefix, sizeof(prefix) - 1) >> > + * >> > + * But this can lead to bugs due to typos, or if prefix is a pointer >> > + * and not a constant. Instead use has_prefix(). >> > + * >> > + * Returns: 0 if @str does not start with @prefix >> > + strlen(@prefix) if @str does start with @prefix >> > + */ >> > +#define has_prefix(str, prefix) \ >> > + ({ \ >> > + const char *____prefix____ = (const char *)(prefix); \ >> > + int ____len____ = strlen(____prefix____); \ >> > + strncmp(str, ____prefix____, ____len____) == 0 ? \ >> > + ____len____ : 0; \ >> > + }) >> >> I think all the underscores are unnecessary and confusing. >> > > Well, perhaps I can just remove the ending ones. I get paranoid with > macro variables, and tend to over do it so that there's no question.
Why not make it an inline function?
Andreas.
-- Andreas Schwab, schwab@linux-m68k.org GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1 "And now for something completely different."
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