Re: [PATCH v2] Mark win32's pthread_exit() as NORETURN
Am 01.03.2016 um 15:13 schrieb Johannes Schindelin:
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> The pthread_exit() function is not expected to return. Ever. On Windows,
> we call ExitThread() whose documentation claims: "This function does not
> return a value.":
>
> https://msdn.microsoft.com/en-us/library/windows/desktop/ms682659
This is misleading: MSDN marks all functions declared void as "does not return a value," for example, look at EnterCriticalSection:
https://msdn.microsoft.com/en-us/library/windows/desktop/ms682608
For this reason, I actually prefer your version 1 patch without the explanation.
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>
> Pointed out by Jeff King.
>
> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> ---
>
> Relative to v1, only the commit message changed (to clarify that
> ExitThread() indeed never returns).
>
> compat/win32/pthread.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/compat/win32/pthread.h b/compat/win32/pthread.h
> index 20b35a2..148db60 100644
> --- a/compat/win32/pthread.h
> +++ b/compat/win32/pthread.h
> @@ -78,7 +78,7 @@ extern int win32_pthread_join(pthread_t *thread, void **value_ptr);
> #define pthread_equal(t1, t2) ((t1).tid == (t2).tid)
> extern pthread_t pthread_self(void);
>
> -static inline int pthread_exit(void *ret)
> +static inline int NORETURN pthread_exit(void *ret)
I would have written it as
#ifdef __GNUC__ __attribute__((__noreturn__)) #endif static inline int pthread_exit(void *ret) ...
but I can live with your version as long as it compiles.
Your solution is pragmatic: NORETURN is defined in git-compat-util.h, and by using it here, we depend on that pthread.h is included sufficiently late that the macro is available at this point. The instance in compat/nedmalloc/malloc.c.h is bracketed with #ifndef WIN32 so that it is not compiled on Windows, all other instances are after git-compat-util.h or cache.h or in headers that are to be included only after git-compat-util.h or cache.h per convention. Looks like we are safe.
> {
> ExitThread((DWORD)(intptr_t)ret);
> }
>
Johannes Schindelin
