[Xcb] [EXTERNAL] - Attempt at writing a tutorial

Lucas Augusto Valentim Dantas lucasvalentim at outlook.com.br
Thu Feb 11 17:58:49 UTC 2021


Thank you very much! I will ruminate more on this and read on error handling and events until I can write something intelligible about this.
Meanwhile I would like to point out that the struct I was talking about has the following members: major_opcode, pad0 (no idea what this is nor how it is used), length (length of the request?), and window (I kknow this is supposed to reference the window that is supposed to be unmapped).

https://xcb.freedesktop.org/manual/structxcb__unmap__window__request__t.html
It also appears here https://refspecs.linuxfoundation.org/LSB_5.0.0/LSB-Desktop-generic/LSB-Desktop-generic/libxcb-ddefs.html

________________________________
De: Uli Schlachter <psychon at znc.in>
Enviado: quinta-feira, 11 de fevereiro de 2021 14:37
Para: Lucas Augusto Valentim Dantas <lucasvalentim at outlook.com.br>; xcb at lists.freedesktop.org <xcb at lists.freedesktop.org>
Assunto: Re: [Xcb] [EXTERNAL] - Attempt at writing a tutorial

Hi,

checked vs unchecked requests are explained here (under the heading of
the same name):

https://www.systutorials.com/docs/linux/man/3-xcb-requests/

The short version is: This only makes a difference for X11 error
handling. With unchecked requests, any errors show up as events in e.g.
xcb_wait_for_event(). With checked requests, errors are provided when
getting the reply (or calling xcb_check_request()).

Cheers,
Uli

Am 11.02.21 um 18:28 schrieb Lucas Augusto Valentim Dantas:
> I found those values by looking into the source code, probably libxcb's, since they are passed to the second argument of the function xcb_send_request(), as can be seen here (although the "sequence" argument is gone already): https://xcb.freedesktop.org/ProtocolExtensionApi/#index3h2 but that page doesn't explain what they do.
> My goal with this tutorial is to provide enough for the reader to understand the X documentation so he is able to "navigate" on his own, that is what I am trying to do myself.
> ________________________________
> De: Peter Harris <pharris at opentext.com>
> Enviado: quinta-feira, 11 de fevereiro de 2021 14:15
> Para: Lucas <lucasvalentim at outlook.com.br>; xcb at lists.freedesktop.org <xcb at lists.freedesktop.org>
> Assunto: RE: [EXTERNAL] - [Xcb] Attempt at writing a tutorial
>
> On 2021-02-10 Lucas wrote:
>> I am writing a XCB tutorial as an exercise, so far, this is what I
>> have https://biteiro.ga/xcb.html
>>
>> There are a few things I couldn't find details yet, such as what does
>> the flags XCB_REQUEST_CHECKED, XCB_REQUEST_RAW,
>> XCB_REQUEST_DISCARD_REPLY, and XCB_REQUEST_REPLY_FDS do?
>
> Those values are for internal use by libxcb (and/or xlib), and are not intended to be used by a normal user of libxcb.
>
> Who is your tutorial intended for? Showing the inner workings is more of a "deep documentation" thing than a "tutorial" thing.
>
>> Are there any
>> explanations on the members of the struct xcb_unmap_window_request_t?
>
> libxcb is a thin wrapper around the X11 protocol. As such, the documentation for those fields can be found at:
>
> https://www.x.org/releases/X11R7.7/doc/xproto/x11protocol.html#request_format
>
> https://www.x.org/releases/X11R7.7/doc/xproto/x11protocol.html#requests:UnmapWindow
>
> Peter Harris
>
>
> _______________________________________________
> Xcb mailing list
> Xcb at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/xcb
>


--
<alanc> I think someone had a Xprint version of glxgears at one point,
    but benchmarking how many GL pages you can print per second
    was deemed too silly to merge
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