[ale] Help with C project

[Pete Hardie]

Is process_stop() being called from the running thread, or from the
scheduler thread?

On Sat, Jan 23, 2016 at 2:41 PM, Christopher Hagler <
haglerchristopher at gmail.com> wrote:

> Thank you for the reply. When I create a process, I give each thread their
> own condition variable because I can control which threads are run. I have
> a function called process_create that in turn calls pthread_cond_init. From
> my understanding a call to pthread_cond_signal does not guarantee
> scheduling order. Threads are not scheduled in the order they call
> pthread_cond_wait. This is why I give each thread their own condition
> variable. The scheduler will call process_start that will call
> pthread_cond_signal on the process struct passed in as a parameter. All of
> that works correctly. However a call to process_stop which calls
> pthread_cond_wait does not seem to work. From what I have read, it all
> seems correct, but the threads continue to run.
> On Jan 23, 2016 12:40 PM, "Pete Hardie" <pete.hardie at gmail.com> wrote:
>
>> It's been a while since I use pthreads directly, but the modus operandi
>> of condition variables is that you declare one before the
>> threads that use it are started, and the threads that you want to wait
>> will call wait() to pause until the another thread signals a change,
>> and then you would check the condition variable value to see if it is the
>> desired value to proceed.
>>
>> On Sat, Jan 23, 2016 at 11:52 AM, Christopher Hagler <
>> haglerchristopher at gmail.com> wrote:
>>
>>> I am working on a home automation project written in C. It allows a user
>>> to automate daily task with open source hardware and software. However,
>>> since I am lacking experience with pthreads, I have run into a couple of
>>> issues that I cant seem to resolve. The intentions of the code where the
>>> issues reside are:
>>>
>>> The project allows drivers to be written as shared objects that, which
>>> in turn, will control a remote hardware device or devices with all
>>> communication happening through shared memory. The Scheduler module will
>>> take the shared object, and schedule it to run via process queues. Once the
>>> process, a struct containing the shared object and an abstraction for a
>>> pthread, runs for its time slot, the scheduler will stop the process and
>>> place it in another process queue. The whole idea was to simulate an
>>> operating system scheduler because potentially there could be a few hundred
>>> threads. This is where the first issue resides. I am having trouble putting
>>> the process to sleep. I have done some research on pthreads and supposedly
>>> this can be accomplished via pthread condition variables. This is the
>>> solution I have attempted, and apparently I have not implemented it
>>> correctly. It will start the process which will run, but when I try to put
>>> it to sleep, it keeps running.
>>>
>>> The second issue is when ever you run the program, it fails to link the
>>> shared object sometimes. However, if you have to quickly run the program
>>> back-to-back, it will start and run fine. I am not sure why this is
>>> happening. It could possibly be linked to my setup, but I am not sure. I am
>>> running Opensuse in Virtual Box.
>>>
>>> Any advice on these issues would be greatly appreciated. I also know
>>> there are a couple of people who have been wanting to learn C, and you are
>>> more than welcome to join the project if you want.
>>>
>>> The code base:
>>> https://github.com/haglerchristopher/automation/tree/development
>>>
>>> Thanks for the help.
>>>
>>> _______________________________________________
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>>> http://mail.ale.org/mailman/listinfo
>>>
>>>
>>
>>
>> --
>> Pete Hardie
>> --------
>> Better Living Through Bitmaps
>>
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>>
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>


-- 
Pete Hardie
--------
Better Living Through Bitmaps
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