🚀 go-pugleaf

In article <28efue$478@access.digex.net> kbennett@access.digex.net (Keith R. Bennett) writes:

>   I have a question about thread programming.  Is there any way to make
>   a given variable specific to an instance of a thread?
>
>   The best I can think of so far is to use either local variables, or
>   variables allocated from the heap.  There is a large number of
>   these variables that will be thread-specific, so I was thinking
>   of putting them in structures and creating a new instance of each
>   structure for each thread.
>
>   The C++ programmers guide mentions that there is a separate copy of
>   errno for each thread.  Can I do that with my own variables?

There is a feature supplied by C Set/2 library called _threadstore.
It gives the address of a (void *) which is private to each thread.
You can put a pointer to thread-local information into this pointer:

void mythread(void *threadparam)
{
    struct thread_info info;    /* Allocate thread-private info on
                                   this thread's stack */

    *_threadstore = &info;      /* Place that private info's
                                   address into _threadstore */

[...]

elsewhere(void)
{
    struct thread_info *info = *_threadstore;
-- 
Richard Krehbiel          rich@kastle.com or richk@grebyn.com
OS/2 will do for me until AmigaDOS for the 386 comes along...