On 4 October 2014 23:05, Dan Fandrich <dan_at_coneharvesters.com> wrote:
> On Sat, Oct 04, 2014 at 04:55:40PM -0400, K. Frank wrote:

>> First, do I understand correctly that if, say, I were to have
>> main() in a perfectly ordinary C program spawn a thread
>> (say, pthread_create), then it would be illegal for that thread
>> to call curl_global_init (even if no other thread in the program
>> were to call any curl functions)?
>
> Yes. But sometimes you will be lucky and it will work.

I believe this is a too generic statement. It is not threads per se
that is the problem - after all, on Linux and some other systems
there's nothing inherently different between the thread that runs
main() or any other thread - they are all just threads. Some processes
happen to have more than one thread, that's all.

The issue is about race condtions only. If main() spawns a single
thread which then goes on to do curl_global_init() and then manages
all its own threads from there, then that's the same as if main()
itself did it.
What you cannot do (and that follows from the above) is to spawn
multiple threads with copies of that code which may call
curl_global_init().. if you do, then you will have to take care and
play around with flags and mutexes etc. And that would indicate a
non-optimal design.
-------------------------------------------------------------------
List admin: http://cool.haxx.se/list/listinfo/curl-library
Etiquette: http://curl.haxx.se/mail/etiquette.html
Received on 2014-10-06