[Freeciv-Dev] Re: (PR#2370) Path finding

["Jason Short via RT" <rt@xxxxxxxxxxxxxx>]

Raimar Falke via RT wrote:
> On Sat, Nov 23, 2002 at 03:43:45PM -0800, rwetmore@xxxxxxxxxxxx via RT wrote:
> 
>>At 08:57 AM 02/11/23 -0800, Raimar Falke via RT wrote:
>>
>>>On Sat, Nov 23, 2002 at 07:52:45AM -0800, Per I. Mathisen via RT wrote:
>>>
>>>>On Sat, 23 Nov 2002, Raimar Falke via RT wrote:
>>>>
>>>>>First: inlining. It is critical that this is done. Gregory uses macros
>>>>
>>>>...
>>>>
>>>>>while I use the inline keyword. Both can provide the same results.
>>>>
>>>>That Greg's version does not need to open the inline can of worms is a
>>>>good thing. If we do add inline at a later time, his macros can always be
>>>>turned into functions at that time.
>>>
>>>I'm still for inline and I would like to restart the discussion.
>>
>><Begin discussion>
>>Inline is very bad. 

I much prefer inline to macros.

>>It does not optimize as well so even when inlined, the performance
>>is not as good as macros.
> 
> 
> Examples?

A while ago, Gaute did some tests with normalize_map_pos inlined versus 
macro'd.  The results were faster when inlined.  The difference was small.

This was with an old version of gcc.  I would like to see new numbers 
with gcc 3.  But either way, I do think it is _harder_ for the compiler 
to optimize inline functions.

>>Big inline functions are an abuse of the technique, when big is big is
>>also ambiguous with inline in addition to the compiler issues above.
> 
> 
> Not a real point.

In fact a negative point :-).  This argument applies much more quickly 
to function-style macros.

>>There is nothing good to say about inlining.
>><End discussion>
> 
> 
> One valid point raised.

There are a couple of others:

- Macros give you some abilities functions don't, obviously.  Take the 
***_iterate macros.  But when this comes to function-style macros, it 
usually just means you have the ability to give weird side effects if 
you want to.

- Less obviously, functions give you some abilities macros don't.  The 
main thing that comes to mind is the easy ability to return a value in a 
more-than-one-line function/macro.

jason