Re: How do I printk <type> correctly?

From: Randy Dunlap
Date: Wed Nov 05 2008 - 13:24:19 EST


On Thu, 23 Oct 2008 15:41:33 +0400 Alexey Dobriyan wrote:

> If variable is of Type use printk format specifier.
> ---------------------------------------------------------
> int %d or %x
> unsigned int %u or %x
> long %ld ot %lx
> unsigned long %lu or %lx
> long long %lld or %llx
> unsigned long long %llu or %llx
> size_t %zu or %zx
> ssize_t %zd or %zx

Add, or is this one too infrequent to be listed here?

tcflag_t %lu or %lx or %lo

Since tcflag_t is unsigned int (on most $ARCH-es) or unsigned long (on sparc32),
use a cast to (unsigned long)flag when printing it.

[Yes, a sparc32 build gets lots of printk format warnings when printing tcflag_t
values.]


> Raw pointer value SHOULD be printed with %p.
>
> u64 SHOULD be printed with %llu/%llx, (unsigned long long):
>
> printk("%llu", (unsigned long long)u64_var);
>
> s64 SHOULD be printed with %lld/%llx, (long long):
>
> printk("%lld", (long long)s64_var);
>
> If type is dependent on config option (sector_t), use format specifier
> of biggest type and explicitly cast to it.
>
> Reminder: sizeof() result is of type size_t.
>
> Thank you for your cooperation.
> --

---
~Randy
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/