Re: [PATCH] MSVC: Windows-native implementation for subset of Pthreads API

[Nicolas Pitre <nico@fluxnic.net>]

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On Thu, 5 Nov 2009, Andrzej K. Haczewski wrote:

> 2009/11/5 Nicolas Pitre <nico@fluxnic.net>:
> > On Wed, 4 Nov 2009, Andrzej K. Haczewski wrote:
> >
> > What about:
> >
> > typedef struct {
> >        HANDLE handle;
> >        void *(*start_routine)(void *);
> >        void *arg;
> > } pthread_t;
> >
> > DWORD __stdcall windows_thread_start(LPVOID _self)
> > {
> >        pthread_t *self = _self;
> >        void *ret = self->start_routine(self->arg);
> >        return (DWORD)ret;
> > }
> >
> > static inline int pthread_create(pthread_t *thread, const void *unused,
> >                                 void *(*start_routine)(void *), void *arg)
> > {
> >        thread->handle = CreateThread(NULL, 0, windows_thread_start,
> >                                      thread, 0, NULL);
> >        [...]
> > }
> 
> The problem I see is not with pthread_init, but pthread_join. Here's
> how it looks:
> 
> int pthread_join(pthread_t thread, void **value_ptr);
> 
> If pthread_t would be a struct, then we can't call pthread_join like
> that...

Why not?  At least gcc is quite happy with such a construct.  It 
probably makes a copy of the stack before passing it though.

> At least that's what I though yesterday, but maybe it can be done like 
> this:
> 
> int win32_pthread_join(pthread_t *thread, void **value_ptr)
> {
>         [...]
> }
> 
> #define pthread_join(a, b) win32_pthread_join(&(a), (b))
> 
> That way we don't need allocations to simulate pthread init/join API

Right.


Nicolas