libgcj and the NPTL posix threads implementation

Mon Mar 1 22:16:00 GMT 2004

Anthony Green writes:
 > 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.
It won't be so very long until all this stuff really is stable. Give
it 6 months or so.
Andrew.