On Wed, Dec 02, 2015 at 04:20:59PM +0300, Alexander Zarochentsev wrote:
> > BAD: if (rc != 0)
> > GOOD: if (rc)
>
> The latest suggestion is not correct,
> from http://wiki.lustre.org/Lustre_Coding_Guidelines :
> Conditional boolean (if (expr)), scalar (if (val != 0)) and pointer
> (if (ptr != NULL)) expressions should be written consistently.
Kernel style trumps Lustre style. Double negative don't not hurt
readability. != NULL is a checkpatch.pl warning. Also comparisons like
== false or == true are checkpatch warnings.
I can think of two places where comparing with zero is appropriate and
those are:
1) If you are talking about the numer zero.
if (x == 0 || x == 2)
2) strcmp() and other *cmp() functions.
if (strcmp(foo, bar) == 0) /* foo and bar are the same */
if (strcmp(foo, bar) < 0) /* foo less than bar */
if (strcmp(foo, bar) != 0) /* foo not the same as bar */
For "if (rc) {" a zero return doesn't mean zero, it means success so
comparing against zero is bad style.
regards,
dan carpenter
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