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Okay, I'm getting it. Not a knock on the author, but looking at this macro'd, pointer-to-void'd stuff certainly makes me appreciate the STL. Edit: aha, I see "

Okay, I'm getting it. Not a knock on the author, but looking at this macro'd, pointer-to-void'd stuff certainly makes me appreciate the STL. Edit: aha, I see "intrusive" was the keyword I was missing to learn all about this different style.

codr7 7y ago
It's all about control and flexibility. If you don't need it you shouldn't pay the price. Having spent quite some time trying to bend the STL to my exact requirements, I don't mind so much.
DSMan195276 7y ago
Using `container_of` lets you avoid having to use void pointers. And the macros like foreach are surprisingly readable once you give them a shot, and they're simple enough they don't really have any big gotchas in how they work. Not every `container_of` data structure is perfect, but in general I'd say they're just as nice to use as any other language's data structures (Though `container_of` is flexible in different ways). The only big downside is that it not part of the C standard, leading to more than a few implementations, some more featureful than others. This one is probably the "least featureful" version I've seen, which may be intentional. The Linux Kernel's implementation has a lot more utility things like looping in different ways and different types of list manipulations. Some are highly useful, others not at much.
rafa1981 7y ago
Intrusive lists are very different beasts than lists by value. There are less allocations involved (perf and points of failure), values can be inserted on different lists without new allocations, deletion is O(1), elements can be heterogeneous (different sizes and types), etc etc I seldomly use linked lists, but most of the time i prefer them to be intrusive. There of course are intrusive list implementations on C++.
- jcheng 7y ago
  > values can be inserted on different lists without new allocations Not multiple lists at the same time, surely...?
  - DSMan195276 7y ago
    They were talking about taking a value off of one list and adding it to a different one, which doesn't require an allocation, but the entity is never on more than one list at a time in that scenario. That said, you can add an entity onto multiple lists if it contains multiple nodes embedded inside. You have to keep track of which nodes are attached to which lists though (Which generally just means being consistent on which you use where). If you give them decent names, then it's not usually a problem, but it can sometimes get a little confusing if you're not careful.
  - rafa1981 7y ago
    Obviously not
- codr7 7y ago
  Same here. Using non-intrusive linked lists just feels wrong once you've gotten used to the idea of embedding links, I find there are always better options. Intrusive lists on the other hand is simply the best solution in some cases.
deleted 7y ago
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codr7 7y ago

It's all about control and flexibility. If you don't need it you shouldn't pay the price. Having spent quite some time trying to bend the STL to my exact requirements, I don't mind so much.

DSMan195276 7y ago

Using `container_of` lets you avoid having to use void pointers. And the macros like foreach are surprisingly readable once you give them a shot, and they're simple enough they don't really have any big gotchas in how they work. Not every `container_of` data structure is perfect, but in general I'd say they're just as nice to use as any other language's data structures (Though `container_of` is flexible in different ways). The only big downside is that it not part of the C standard, leading to more than a few implementations, some more featureful than others. This one is probably the "least featureful" version I've seen, which may be intentional. The Linux Kernel's implementation has a lot more utility things like looping in different ways and different types of list manipulations. Some are highly useful, others not at much.

rafa1981 7y ago

Intrusive lists are very different beasts than lists by value. There are less allocations involved (perf and points of failure), values can be inserted on different lists without new allocations, deletion is O(1), elements can be heterogeneous (different sizes and types), etc etc I seldomly use linked lists, but most of the time i prefer them to be intrusive. There of course are intrusive list implementations on C++.

jcheng 7y ago
> values can be inserted on different lists without new allocations Not multiple lists at the same time, surely...?
- DSMan195276 7y ago
  They were talking about taking a value off of one list and adding it to a different one, which doesn't require an allocation, but the entity is never on more than one list at a time in that scenario. That said, you can add an entity onto multiple lists if it contains multiple nodes embedded inside. You have to keep track of which nodes are attached to which lists though (Which generally just means being consistent on which you use where). If you give them decent names, then it's not usually a problem, but it can sometimes get a little confusing if you're not careful.
- rafa1981 7y ago
  Obviously not
codr7 7y ago
Same here. Using non-intrusive linked lists just feels wrong once you've gotten used to the idea of embedding links, I find there are always better options. Intrusive lists on the other hand is simply the best solution in some cases.

deleted 7y ago

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