Re: [dev] dwm bit fields conversion

From: Markus Teich <markus.teich_AT_stusta.mhn.de>
Date: Sun, 14 Jul 2013 23:22:21 +0200

Since this is just uncommon syntax (at least I haven't seen it before)
and it is just used in the declaration I would be ok with it, if an
additional comment explains it. It's not a strong opinion though, just
an idea.

--Markus


Am 2013-07-14 21:32, schrieb Anselm R Garbe:
> On 7 July 2013 16:49, koneu <koneu93_AT_googlemail.com> wrote:
>> In Xdefs.h, Bool is typedef'd as int (= at least 2 bytes, sometimes
>> more, depending on the implementation), of which we set the last bit
>> to 1 or 0.
>> In the Monitor and Client structures dwm uses, we can instead use
>> char bit fields, storing up to 8 Bool values in 1 byte.
>>
>> diff --git a/dwm.c b/dwm.c
>> index 314adf4..83af1f6 100644
>> --- a/dwm.c
>> +++ b/dwm.c
>> _AT_@ -91,7 +91,7 @@ struct Client {
>> int basew, baseh, incw, inch, maxw, maxh, minw, minh;
>> int bw, oldbw;
>> unsigned int tags;
>> - Bool isfixed, isfloating, isurgent, neverfocus, oldstate,
>> isfullscreen;
>> + unsigned char isfixed :1, isfloating :1, isurgent :1,
>> neverfocus :1, oldstate :1, isfullscreen :1, :2;
>> Client *next;
>> Client *snext;
>> Monitor *mon;
>> _AT_@ -121,8 +121,7 @@ struct Monitor {
>> unsigned int seltags;
>> unsigned int sellt;
>> unsigned int tagset[2];
>> - Bool showbar;
>> - Bool topbar;
>> + unsigned char showbar :1, topbar :1, :6;
>> Client *clients;
>> Client *sel;
>> Client *stack;
>
> I find this less readable than the usage of Bool. If memory
> consumption would be a major dwm concern, I'd agree with such a
> suggestion. But there are more important problems to focus on in dwm
> 6.1 (fixed xinerama support).
>
> Best regards,
> Anselm
Received on Sun Jul 14 2013 - 23:22:21 CEST