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From: Kaz Kylheku <643-408-1753@kylheku.com>
Newsgroups: comp.lang.c
Subject: Re: best approach for multithreading (?)
Date: Sun, 8 Dec 2024 03:49:29 -0000 (UTC)
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On 2024-12-07, James Kuyper <jameskuyper@alumni.caltech.edu> wrote:
> On 12/6/24 11:10, Scott Lurndal wrote:
>> Kaz Kylheku <643-408-1753@kylheku.com> writes:
>>> On 2024-12-06, James Kuyper <jameskuyper@alumni.caltech.edu> wrote:
> ...
>>>> C <threads.h> can be implemented as a thin wrapper over POSIX threads.
>>>> The waste is relatively negligible. The differences, were intended to
>>>> allow <threads.h> to also be implemented on non-POSIX systems as
>>>> wrappers for whatever the native threading system was.
>>>
>>> Generally speaking, you can have a function called pthread_create on
>>> non-POSIX systems, and a header <pthread.h>.
>>
>> There are certain requirements of a posix threads implementation that
>> might be impossible for a non-POSIX system to implement efficiently;
>> windows, for example, doesn't support signals.
>
> My words above not-withstanding, I am not in any sense an expert on any
> kind of threading, nor of Windows. What does POSIX require of threads
> with regards to signals?

Off the top of my head, the highlights:

- threads have their own signal masks, inherited from the creator which
  calls pthtead_create.
- signal masks can be manipulated so that a given signal will be
  handled in the context of a desired thread.
- sigwait (and several other functions) can be used by a thread to
  wait for one or more signals, allowing signals to be process
  synchronously, somewhat like message passing.

-- 
TXR Programming Language: http://nongnu.org/txr
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