Re: underscores and function names

[Om <omanakuttan@xxxxxxx>]

Michael R. Hines wrote:
> The ones with underscores usually have matching functions withOUT 
> underscores. They are meant to be private calls.
>
> The ones without underscores usually call the one with underscores, and 
> these are the ones that actually do the work.
>
> The kernel will sometimes call the underscore'd functions directly 
> because it knows what it's doing.......
>
> But while programming, we should generally call the ones without them.
Yes, unless we know what we do ;-)
for example, lets take arch/i386/lib/usercopy.c : copy_to_user(). This 
function performs some checks (access_ok()) on the passed parameter and 
then call the actual function that implements the functionlity 
include/asm/uaccess.h:__copy_to_user(). The implementation might use 
other functions as well.

If the target area is already checked for access_ok, then the caller 
call skip the call copy_to_user() and make a call directly to 
__copy_to_user(). This will save some time/code size.

I am not familiar with functions with single underscore starting. But 
the idea is same.

HTH.
Om.

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