> and how performance workarounds turn out a poor man's GC.
If you need performance then it doesn't matter if it is a "poor mans GC", what matters is that it meets the space/time requirements, most general purpose GC tend to care about neither.
Sometimes you can't do that though because you have certain constraints on the execution order of whatever routines you need to run. This is completely independent of whether you use manual cleanup or GC or RAII, however with GC it is weird/hard/impossible to synchronize the GC with the non-cleanup code.
I had a AAA project hitting 30ms pauses in free() implementation by platform vendor for quite popular gaming platform in 2016. Ofc it is anecdata but having actual deadlines from implementations is really hard. I had to replace malloc/free implementation like 3 month before ship date to avoid the issue.
Anyway, for complex state that must be cleaned up, maybe flushed before etc., you'll always find a lot of manual cleanup code, or otherwise find code with lots of random problems, often unreported. That is true both for GC languages as well as C++ and other languages with RAII or RAII-likes.
The talk is "Leak-Freedom in C++", 2016 actually, https://youtu.be/JfmTagWcqoE?si=MY1JnWyybh5K8I8-
An optimization that coroutines rely upon as means to remove the abstractions of their execution.
I can't imagine what LTO should have to do with that either, but if there's any substance here please enlighten me.
The order in which destructors get called is well defined (and generally useful insofar as it's the reverse order of construction). Can't you just accept a simple argument? I'm not even a huge fan of RAII, but it has its uses.
Similarly, the construction/destruction order for std::tuple elements is not well defined.
Granted, that's implementation defined behavior, which is technically deterministic on a single compiler.
I suppose the destruction of whatever the expressions constructed still happens in reverse order of construction.
But either way I might not even care, I'm aware that at the level of a single statement the execution sequences aren't much defined, so I rarely put more than one mutating thing per expression, or otherwise I'm sure that I don't care about the order -- I could live with any sequence as well as totally parallel execution.
Example: buf[i++] = 5 has 2 mutating sub-expressions, but I know it's not messing up anything. I don't care whether i gets incremented before 5 gets assigned or the other way around.
Of course, you can also do manual allocations if you really wanted to, but - with the changes in the language since C++11 - you just don't have the motivation to do it.
Manually managed code doesn't crash all the time. It probably crashed way more in the 90s. There is an art to writing manually managed code that is maintainable and fast, sure, and it doesn't involve malloc() and free(). And then there is RAII, automating lots of the work.
The C++ crazies are AFAICS still most everywhere where there is lots of temporary objects and serious requirements on throughput & latency. There are frameworks and languages that support garbage collection that get used in this space too, but I don't know how much can be inferred from that.
Seems like C and C++ guys are constantly looking for ways to automate their garbage cleanup.
And seems like GC guys are constantly looking for ways to fix their web-of-objects memory layout, and to prevent GC from ruining their performance. Plus, GC isn't deterministic, it mostly works for memory but otherwise you'll see _lots_ of manual cleanup code (not actually making use of the GC for this cleanup type code), and it always feels a bit tricky with the GC still being part of the game. Not that I take a huge issue with C-like cleanup code -- I think RAII can be tricky too because it's hard to "read" what happens. But compared to GC, at least RAII is deterministic.