| Message ID | a3f07198ba9e12b45ef38b45fa543e9b597ee70f.1629578875.git.qemu_oss@crudebyte.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | introduce QArray | expand |
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 */ >
On Sonntag, 22. August 2021 06:11:58 CEST Richard Henderson wrote: > 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~ Ah, you are right. I was trying it, but now as you pointed me at it again, I realized I was just missing something. The specific use case here is like: struct Foo { ... } Foo; Foo *var; _Static_assert(__builtin_types_compatible_p(Foo, typeof(*var)), "type mismatch"); So I was missing the typeof() keyword to deduce the scalar type from the passed variable. I'll send a v2. Thanks! Best regards, Christian Schoenebeck
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 */
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. Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com> --- include/qemu/qarray.h | 6 ++++++ 1 file changed, 6 insertions(+)