Re: [PATCH 2/5] qemu/qarray.h: weak scalar type check in QARRAY_CREATE()

[Richard Henderson]

On 8/21/21 1:30 PM, Christian Schoenebeck wrote:
> Unfortunately something like
>
>    _Static_assert(typeof(a) == typeof(b), "type mismatch");
>
> is currently not suported by C. So for the time being at least
> check that the size of the scalar types match at compile time.

Did you try
_Static_assert(__builtin_types_compatible_p(X, Y), "type mismatch");


r~

> Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
> ---
>   include/qemu/qarray.h | 6 ++++++
>   1 file changed, 6 insertions(+)
>
> diff --git a/include/qemu/qarray.h b/include/qemu/qarray.h
> index 230a556e81..2cb8656c5d 100644
> --- a/include/qemu/qarray.h
> +++ b/include/qemu/qarray.h
> @@ -27,6 +27,8 @@
>   #ifndef QEMU_QARRAY_H
>   #define QEMU_QARRAY_H
>   
> +#include "qemu/compiler.h"
> +
>   /**
>    * QArray provides a mechanism to access arrays in common C-style (e.g. by
>    * square bracket [] operator) in conjunction with reference variables that
> @@ -143,6 +145,10 @@
>    * @param len - amount of array elements to be allocated immediately
>    */
>   #define QARRAY_CREATE(scalar_type, auto_var, len) \
> +    QEMU_BUILD_BUG_MSG( \
> +        sizeof(scalar_type) != sizeof(*auto_var), \
> +        "QArray scalar type mismatch" \
> +    ); \
>       qarray_create_##scalar_type((&auto_var), len)
>   
>   #endif /* QEMU_QARRAY_H */