Re: [PATCH] cpufreq: mvebu: fix integer to pointer cast

[Mason <slash.tmp@free.fr>]

On 07/06/2016 13:30, Ben Dooks wrote:

> Fix the use of 0 instead of NULL to clk_get() call. This stops the
> following warning:
> 
> drivers/cpufreq/mvebu-cpufreq.c:73:40: warning: Using plain integer as NULL pointer

May I ask which compiler/version produced that diagnostic?


> -		clk = clk_get(cpu_dev, 0);
> +		clk = clk_get(cpu_dev, NULL);

Quoting C99 6.3.2.3 Pointers clause 3

> An integer constant expression with the value 0, or such an expression cast to type
> void *, is called a null pointer constant. If a null pointer constant is converted to a
> pointer type, the resulting pointer, called a null pointer, is guaranteed to compare unequal
> to a pointer to any object or function.

In fact, some implementations merely #define NULL 0
(which, admittedly, creates problems when NULL is used as a parameter
to variadic functions)

Regards.