Re: A problem about reading the source code

Hi,

Am 01.01.24 um 14:39 schrieb starcold14:
> Hi=EF=BC=8CUli Schlachter=EF=BC=8C
> I am very grateful for your reply.
> I am now a little confused about the XML specification. I cannot unders=
tand how
> the XML specification describes a function like xcb_grab_pointer_reply(=
) .
> Is there any documents describe the rules of turning XML to C code?

I don't know about such a document. But the rule is quite simple, I think=
.

The <request> tag provides the name of the request. Since it contains a=20
<reply> tag, the request has a reply (some requests do not generate a=20
reply). Thus, a function xcb_NameOfTheRequest_reply() is generated. The=20
contents of that function is always the same: a call to=20
xcb_wait_for_reply(). It's just that the result of xcb_wait_for_reply()=20
needs to be cast to xcb_NameOfTheRequest_reply_t.

What the XML really describes are the contents of the struct, in this=20
case xcb_grab_pointer_reply_t. There is a single field called "status"=20
in our case here.

I don't know why you want to look at the source code of=20
xcb_grab_pointer_reply(), but there is nothing interesting there.=20
Perhaps it makes more sense to talk about that reason.

Cheers,
Uli

[...]
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> On 12/29/2023 21:00=EF=BC=8CUli Schlachter<[email protected]> <mailto:psyc=
[email protected]> wrote=EF=BC=9A
>=20
>      Hi starcold,
>=20
>      Am 29.12.23 um 09:37 schrieb starcold14:
>=20
>          Hi=EF=BC=8C
>          I'm a newbie and don't know much about libxcb,
>=20
>=20
>      There is xcb/proto and libxcb. proto contains a XML description of=
 the
>      X11 protocol and libxcb uses this XML to generate C code.
>=20
>          and I'm currently having a
>          problem where when I want to find a function named xcb_grab_po=
inter_reply, I
>          can't find it in the code from
>          gitlab(https://gitlab.freedesktop.org/xorg/lib/libxcb
>          <https://gitlab.freedesktop.org/xorg/lib/libxcb>) using the gr=
ep tool.
>=20
>=20
>      You can find he XML specification for GrabPointer here: [0]
>=20
>      [0]:
>      https://gitlab.freedesktop.org/xorg/proto/xcbproto/-/blob/1388374c=
7149114888a6a5cd6e9bf6ad4b42adf8/src/xproto.xml#L2585-2596
>=20
>      When you build libxcb from source, the appropriate C code is then
>      generated. You won't find much helpful in there. This is the gener=
ated
>      code for xcb_grab_pointer_reply():
>=20
>      xcb_grab_pointer_reply_t *
>      xcb_grab_pointer_reply (xcb_connection_t           *c,
>      xcb_grab_pointer_cookie_t   cookie  /**< */,
>      xcb_generic_error_t       **e)
>      {
>      return (xcb_grab_pointer_reply_t *) xcb_wait_for_reply(c,
>      cookie.sequence, e);
>      }
>=20
>      Cheers,
>      Uli
>      --
>      =E2=80=9CSome people are worth melting for.=E2=80=9D - Olaf
>=20

--=20
Homophobia - The fear that another man will treat you the way you treat=20
women.