diff options
| author | Stefan Hajnoczi <stefanha@redhat.com> | 2018-06-14 17:44:31 +0100 |
|---|---|---|
| committer | Stefan Hajnoczi <stefanha@redhat.com> | 2018-06-27 13:01:40 +0100 |
| commit | f18793b096e69c7acfce66cded483ba9fc01762a (patch) | |
| tree | e7cd11a399bfd2f38f81d3c60a010b6a060927d4 /include | |
| parent | 00928a421d47f49691cace1207481b7aad31b1f1 (diff) | |
compiler: add a sizeof_field() macro
Determining the size of a field is useful when you don't have a struct
variable handy. Open-coding this is ugly.
This patch adds the sizeof_field() macro, which is similar to
typeof_field(). Existing instances are updated to use the macro.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 20180614164431.29305-1-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/hw/xen/io/ring.h | 2 | ||||
| -rw-r--r-- | include/qemu/compiler.h | 2 |
2 files changed, 3 insertions, 1 deletions
diff --git a/include/hw/xen/io/ring.h b/include/hw/xen/io/ring.h index abbca47687..ffa3ebadc8 100644 --- a/include/hw/xen/io/ring.h +++ b/include/hw/xen/io/ring.h @@ -65,7 +65,7 @@ typedef unsigned int RING_IDX; */ #define __CONST_RING_SIZE(_s, _sz) \ (__RD32(((_sz) - offsetof(struct _s##_sring, ring)) / \ - sizeof(((struct _s##_sring *)0)->ring[0]))) + sizeof_field(struct _s##_sring, ring[0]))) /* * The same for passing in an actual pointer instead of a name tag. */ diff --git a/include/qemu/compiler.h b/include/qemu/compiler.h index 9f762695d1..5843812710 100644 --- a/include/qemu/compiler.h +++ b/include/qemu/compiler.h @@ -64,6 +64,8 @@ (type *) ((char *) __mptr - offsetof(type, member));}) #endif +#define sizeof_field(type, field) sizeof(((type *)0)->field) + /* Convert from a base type to a parent type, with compile time checking. */ #ifdef __GNUC__ #define DO_UPCAST(type, field, dev) ( __extension__ ( { \ |