[m-users.] What is "thread-local storage"?

[Volker Wysk]

Am Freitag, dem 15.12.2023 um 23:57 +1100 schrieb Julien Fischer:
> On Fri, 15 Dec 2023, Volker Wysk wrote:
> 
> > In mercury_memory.h, there's this:
> > 
> > // MR_GC_NEW(type):
> > //  Allocates space for an object of the specified type.
> > //  If conservative GC is enabled, the object will be garbage collected
> > //  when it is no longer referenced from GC-traced memory.
> > //  Memory allocated with malloc() (or MR_malloc() or MR_NEW())
> > //  is not GC-traced. Nor is thread-local storage.
> > 
> > I don't understand the "Nor is thread-local storage." part. What is 
> > "thread-local storage"?
> 
> In this context it can refer to values stored using the POSIX threads
> function pthread_setspecific(), or to variables declared using GCC's
> __thread keyword or C11's _Thread_local keyword.

Okay. The documentation for that made it clear, what it is.

> > Do I need to care?
> 
> I can't answer that; I don't know what you are trying to do.

I'm trying to avoid messing with MMC internals, if possible. I was wondering
if I have to deal with that thread-local storage, when I use MR_GC_NEW() in
a multi-threaded program. I take your answer for a "no".

I'm in the second approach to build a thread-safe ODBC library (derived from
the ODBC "extra" library).

Cheers,
Volker