Re: per-thread global variables

["J.A. Magallon" <jamagallon@able.es>]

On 2002.07.13 Robert M. Hyatt wrote:
>
>In the "master thread" I define an array of structures, one per
>thread.  When I start a thread, I pass it the address of its private
>structure.

So:

struct tinfo* data[n];

for (nthreads)
  data[i] = new private struct
  clone(f,data[i])

f(struct tinfo* mydata)
{
  me = mydata->mysefl; // OK till here
  g();
}

g()  // Note I do not pass any tinfo here
{
  // Who am I ?????????
}

You can't call any function from you thread-main function that
needs to self-identify ??

>Note that this has nothing to do with the stack.  Each
>thread _must_ have a stack (mine is 1mb per thread) and you have to
>(on intel) pass the _end_ address since stacks go backward on
>X86 machines.
>
>Another idea is to set up an array of pointers to the private
>(global) structures.  Then have each thread do something
>like pointer[thread_id]->stuff to get to stuff in its private
>structure.
>

We are in the same problem, if thread_id is pid, you need a big array.
If it is not, you need a multi-personality thread_id.

-- 
J.A. Magallon             \   Software is like sex: It's better when it's free
mailto:jamagallon@able.es  \                    -- Linus Torvalds, FSF T-shirt
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