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Re: [Qemu-arm] [Qemu-devel] [PATCH 1/3] qdev-properties.h: Explicitly se
From: |
Markus Armbruster |
Subject: |
Re: [Qemu-arm] [Qemu-devel] [PATCH 1/3] qdev-properties.h: Explicitly set the default value for arraylen properties |
Date: |
Thu, 13 Jul 2017 16:11:59 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/25.2 (gnu/linux) |
Peter Maydell <address@hidden> writes:
> In DEFINE_PROP_ARRAY, because we use a PropertyInfo (qdev_prop_arraylen)
> which has a .set_default_value member we will set the field to a default
> value. That default value will be zero, by the C rule that struct
> initialization sets unmentioned members to zero if at least one member
> is initialized. However it's clearer to state it explicitly.
>
> Signed-off-by: Peter Maydell <address@hidden>
> ---
> If my eyeball of the sources is correct, this is the only case we
> have of a Property struct that uses a PropertyInfo with a non-NULL
> .set_default_value but which doesn't explicitly set .defval.u.
> ---
> include/hw/qdev-properties.h | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/include/hw/qdev-properties.h b/include/hw/qdev-properties.h
> index 0604c33..36d040c 100644
> --- a/include/hw/qdev-properties.h
> +++ b/include/hw/qdev-properties.h
> @@ -110,6 +110,7 @@ extern PropertyInfo qdev_prop_arraylen;
> _arrayfield, _arrayprop, _arraytype) { \
> .name = (PROP_ARRAY_LEN_PREFIX _name), \
> .info = &(qdev_prop_arraylen), \
> + .defval.u = 0, \
> .offset = offsetof(_state, _field) \
> + type_check(uint32_t, typeof_field(_state, _field)), \
> .arrayinfo = &(_arrayprop), \
Hmm.
.info and .defval apply to the array *length*.
.info.set_default_value() is set_default_uint(), which uses .defval.u.
Setting it here is correct.
The array *elements* are described by .arrayinfo. There is no
.arraydefval, but that's okay, because .arrayinfo.set_default_value()
doesn't get called. Correct?
[Qemu-arm] [PATCH 2/3] qdev: support properties which don't set a default value, Peter Maydell, 2017/07/11