Good C programming style

[Skarmander]

Sensei wrote:




How big is "big"?

#define NEEDS(mill, n) \
do { \
if (vm->myHeap->available < (Size) (n)) \
(FREEZE(), millRegenerate( mill ), MELT()); \
} while (0)

#define INLINE inline

INLINE void needs(? mill, Size n) {
if (vm -> myHeap -> available < n) {
freeze();
millRegenerate(mill);
melt();
}
}

S.

 

[Chris Dollin]

#define INLINE inline

INLINE void needs(? mill, Size n) {
if (vm -> myHeap -> available < n) {
freeze();
millRegenerate(mill);
melt();
}
}

Won't work.

FREEZE() is a macro, MELT is a macro, both of them use variables
available where NEEDS is called - such as, for example, `vm`.

And `inline` wasn't routinely available when this code was written;
furthermore, failure to inline is likely to make the code run
significantly more slowly. Since this is part of the system core,
it would matter.

 

[Skarmander]

Skarmander wrote:




Won't work.

FREEZE() is a macro, MELT is a macro, both of them use variables
available where NEEDS is called - such as, for example, `vm`.

Pass as parameters or promote to global status. Probably the latter.
"Global" with respect to the smallest unit appropriate, of course.

And `inline` wasn't routinely available when this code was written;
furthermore, failure to inline is likely to make the code run
significantly more slowly. Since this is part of the system core,
it would matter.

Sure. If inlining really won't work and profiling shows you you do need
that performance, take the macro route.

S.

 

[Chris Dollin]

Pass as parameters or promote to global status. Probably the latter.
"Global" with respect to the smallest unit appropriate, of course.


Sure. If inlining really won't work and profiling shows you you do need
that performance, take the macro route.

Inlining really didn't work.