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Re: emulating tls for systems without

On 06/10/2006, at 3:53 PM, Paolo Carlini wrote:

Geoffrey Keating wrote:

About this, I would be curious to know whether this enhancement
benefits libstdc++/24025, which, if I remember correctly, only affects
systems not defining _GLIBCXX_HAVE_TLS...

It might make it worse.  The thread emulation code abort()s when it
runs out of memory.

Humm, unfortunately I'm missing too many details about the emulation, sorry about that. Do you mean, it essentially allocates on the heap behind the scenes, similarly to the current ! _GLIBCXX_HAVE_TLS case? Thanks in advance for any clarification,

I only looked at it very briefly, but it does:

+static void
+emutls_init (void)
+  __GTHREAD_MUTEX_INIT_FUNCTION (&emutls_mutex);
+  if (__gthread_key_create (&emutls_key, emutls_destroy) != 0)
+    abort ();


+      ptr = malloc (obj->size + sizeof (void *));
+      if (ptr == NULL)
+       abort ();

and so on.

(The big benefit of the non-emulated TLS is that memory is allocated on pthread_create(), so you know that either memory gets allocated or the thread doesn't get created, and either way you don't get random crashes...)

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