Re: what does a number of "_" mean?

[Jan Hudec <bulb@ucw.cz>]

On Mon, Nov 03, 2003 at 11:53:22 -0500, Robert Love wrote:
> On Mon, 2003-11-03 at 08:17, Shinpei Kato wrote:
> 
> > How about types or variables and functions beggining with one "_"
> > as _exit()?
> 
> Underscores tend to denote internal functions, or ones with a
> corresponding functions that are of a "higher level".
> 
> There is not any official difference between one and two underscore
> proceeded functions, but I guess two underscore functions would tend to
> be "more internal" than one underscore functions.

Actualy it's the other way around. _ functions are usualy purely
internal. __ functions are usualy "raw" variants.

> For example, consider foo() and __foo().  foo() might obtain requisite
> locks and then call __foo().  The standard interface would be foo(), but
> you could call __foo() if you knew you already held the locks or
> whatever.

... you often want to call such variant from mostly unrelated code
because the calling convention is appropriate. Note, that (except BKL)
locks in kernel are not recursive.

> In the case of the _exit_*() functions, those are internal helper
> functions called by do_exit().

... on the other hand, you never want to call such a helper.

-------------------------------------------------------------------------------
						 Jan 'Bulb' Hudec <bulb@ucw.cz>
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