Re: memcpy

["Peter Hüwe" <PeterHuewe@gmx.de>]

Am Donnerstag 27 August 2009 00:18:28 schrieb Stoyan Gaydarov:
> I wanted to know what memcpy returned as a result, and if it
> needs/should be checked. There are several places in the kernel where i
> noticed it being used but i also saw a warning about the result not
> being used, so i wanted to know a little more about it.
>
> -Stoyan
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Hi,

*memcpy is defined in .../lib/string.c  (+ some macros etc - use cscope to 
find more references) as

/**
 * memcpy - Copy one area of memory to another
 * @dest: Where to copy to
 * @src: Where to copy from
 * @count: The size of the area.
 *
 * You should not use this function to access IO space, use memcpy_toio()
 * or memcpy_fromio() instead.
 */
void *memcpy(void *dest, const void *src, size_t count)
{
    char *tmp = dest;
    const char *s = src;

    while (count--)
        *tmp++ = *s++;
    return dest;
}

You can see it just returns the destination address that you have passed to it
-> so I guess unless it is possible that you have already passed it a null 
pointer (which might horribly fail) it is not really necessary to check the 
result.


Peter