libgcj and the NPTL posix threads implementation

Mon Mar 1 22:10:00 GMT 2004

On Mon, 2004年03月01日 at 13:42, Jeff Sturm wrote:
> What can you reliably test for, besides catching a signal if TLS isn't
> available?

I think we'd want to do something like this for x86...
static int using_NPTL = 0;
...and...
#ifdef _CS_GNU_LIBPTHREAD_VERSION
 size_t n = confstr (_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
 if (n > 0)
 {
 char* buf = (char*)alloca(n);
 confstr(_CS_GNU_LIBPTHREAD_VERSION, buf, n);
 if (strstr (buf, "NPTL"))
 using_NPTL = true;
 }
#endif
..and..
inline _Jv_ThreadId_t
_Jv_ThreadSelf (void)
{
 if (using_NPTL)
 {
 size_t id;
 asm ("mov %%gs:0x0, %0" : "=r"(id));
 return id;
 } else {
 ...use Boehm's caching thread identity code...
 }
}
I think this would always work, but I really wish we didn't have to.
AG
-- 
Anthony Green <green@redhat.com>
Red Hat, Inc.