[FFmpeg-devel] [PATCH] w32pthreads: Fix function signature mismatches for CreateThread

[Martin Storsjö]

On Wed, 2 Aug 2023, Martin Storsjö wrote:

> In WinRT mode, we use CreateThread instead of _beginthreadex.
>
> CreateThread takes a LPTHREAD_START_ROUTINE function pointer,
> which has got the signature DWORD WINAPI ThreadProc(LPVOID).
> _beginthreadex takes a function with the signature
> unsigned __stdcall func(void *).
>
> DWORD is defined as an unsigned long, which is different type
> from unsigned int, even if they have the same size on Windows.
>
> This fixes build failures with Clang 16 and newer, where function
> pointer type mismatches are a fatal error by default.
> ---
> compat/w32pthreads.h | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/compat/w32pthreads.h b/compat/w32pthreads.h
> index 6405e72b64..dae8d9420d 100644
> --- a/compat/w32pthreads.h
> +++ b/compat/w32pthreads.h
> @@ -66,7 +66,14 @@ typedef CONDITION_VARIABLE pthread_cond_t;
> #define PTHREAD_CANCEL_ENABLE 1
> #define PTHREAD_CANCEL_DISABLE 0
>
> -static av_unused unsigned __stdcall attribute_align_arg win32thread_worker(void *arg)
> +#if HAVE_WINRT
> +#define THREADFUNC_RETTYPE DWORD
> +#else
> +#define THREADFUNC_RETTYPE unsigned
> +#endif
> +
> +static av_unused THREADFUNC_RETTYPE
> +__stdcall attribute_align_arg win32thread_worker(void *arg)
> {
>     pthread_t *h = (pthread_t*)arg;
>     h->ret = h->func(h->arg);
> -- 
> 2.34.1

Will push soon if there's no objections, as this is rather trivial.

// Martin