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From: "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com>
Newsgroups: comp.lang.c++,comp.lang.c
Subject: Re: Threads across programming languages
Date: Wed, 1 May 2024 22:20:47 -0700
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On 5/1/2024 1:34 PM, Lawrence D'Oliveiro wrote:
> On Wed, 1 May 2024 10:59:16 +0200, Bonita Montero wrote:
> 
>> Am 01.05.2024 um 10:53 schrieb Lawrence D'Oliveiro:
>>
>>> On Wed, 1 May 2024 10:13:03 +0200, Bonita Montero wrote:
>>>
>>>> Am 01.05.2024 um 09:10 schrieb Lawrence D'Oliveiro:
>>>>
>>>>> On Wed, 1 May 2024 06:54:13 +0200, Bonita Montero wrote:
>>>>>
>>>>>> Boost.ASIO does that all for you with a convenient interface.
>>>>>> If enabled it even uses io_uring or the Windows' pendant.
>>>>>
>>>>> How many languages does it support?
>>>>
>>>> Just C++ ...
>>>
>>> Not much use, then.
>>
>> System-level programming is mostly made with C++.
> 
> No, it is actually mostly C, with Rust making inroads these days.
> 
> And you don’t have to be doing “system-level” programming to be needing
> event-driven paradigms.
> 
>>> But functions and classes are not first-class objects in C++, ...
>>
>> Of course, since C++11.
> 
> No they aren’t. You cannot easily define a C++ function that returns a
> general function or class as a result, just for example.
> 
>>> You cannot define function factories and class factories, like you can
>>> in Python.
>>
>> Python is nothing for me since it is extremely slow.
> 
> Remember, we’re talking about maximizing I/O throughput here, so CPU is
> not the bottleneck.

It can be if your thread synchronization scheme is sub par. I have 
actually seen code where an IOCP completion thread locks a global mutex. 
Something like this pseudo-code:
_________________
for (;;)
{
    iocp_overlapped& p = GQCS(INFINITE);

    lock_mutex(global);

    // process event...

    unlock_mutex(global);
}
_________________
This is really BAD! It will create a rather massive bottleneck under 
times of heavy load... Also, it creates a nasty condition where things 
can become deadlocked if processing the overlapped completion calls into 
unknown user code to do some work. I have had to debug some others code 
like this before. Not exactly fun...