[PATCH 2/2] kernel32: conditional variable support

[Nikolay Sivov]

On 12/29/2012 23:04, Marcus Meissner wrote:
> From: Marcus Meissner <marcus at jet.(none)>
>
> Modeled pretty much after the implementation described
> in glibc/nptl/DESIGN-condvar.txt with its futex usage
> sofar replaced by regular Win32 Semaphores.
>
> An additional futex implementation is possible.
>
> I *think* I have the semantics correct, there is 1 small
> place where it might have unnecessary CPU usage though.
>
> Ciao, Marcus

> +/**********************************************************************
> + *           InitializeConditionVariable     (KERNEL32.@)
> + */
> +VOID WINAPI InitializeConditionVariable(PCONDITION_VARIABLE variable)
> +{
> +    struct _condition_var_intern *var;
> +    variable->Ptr = HeapAlloc(GetProcessHeap(),HEAP_ZERO_MEMORY,sizeof(struct _condition_var_intern));
> +    var = variable->Ptr;
> +    if (!var) return;
> +    InitializeCriticalSection (&var->crit);
> +    var->crit.DebugInfo->Spare[0] = (DWORD_PTR)(__FILE__ ": ConditionVariable.cs");
> +}
I don't think it allocates anything at all, what makes me believe that 
is that stuff like CONDITION_VARIABLE_INIT exists.
After googling a bit for it I see that gallium from mesa has some 
platform dependent stuff in code that uses this API like that:

---
+#define pipe_static_condvar(cond) \
  + /*static*/ pipe_condvar cond = CONDITION_VARIABLE_INIT
---

So this structure has nothing more than a single pointer value, value 0 
of it means it's initialized. I think you could just add some tests to 
see if it's really reset to 0 from initial value.

Also regarding tests I don't think randomizing timeouts is a good idea 
cause it adds some unpredictable behaviour and it's not really clear if 
we could rely on such tests results.