[PATCH libX11] config: Add an option to initialize threads by default.

Rami Ylimäki rami.ylimaki at vincit.fi
Mon Jan 31 06:32:48 PST 2011

On 01/31/2011 04:14 PM, Tiago Vignatti wrote:
> On 01/31/2011 04:06 PM, ext Julien Cristau wrote:
>> On Mon, Jan 31, 2011 at 15:12:29 +0200, Tiago Vignatti wrote:
>>> On 01/31/2011 01:13 PM, ext Julien Cristau wrote:
>>>> On Mon, Jan 31, 2011 at 12:46:56 +0200, Rami Ylimäki wrote:
>>>>> This change makes it possible to guard a system against a missing
>>>>> XInitThreads call in X clients. One might argue that this is a client
>>>>> problem and that all X clients should call XInitThreads if it's
>>>>> possible that they could use Xlib from multiple threads. However,
>>>>> experience has shown that it's just too easy for developers to
>>>>> overlook the need for this call.
>>>> This change means that somebody developing their apps on a system with
>>>> it on will never see they need to call XInitThreads(), and stuff will
>>>> break when moving to an Xlib without that option.  I don't think 
>>>> that's
>>>> a good idea.
>>> I do agree with Julien in the sense that developers could become
>>> lazy and in general won't care much anymore about initializing
>>> thread support.
>>> OTOH, if you pick a Qt application for instance, you will see that
>>> it is close to impossible to track from a stack trace of 80
>>> functions whether XInitThreads() is called properly or not. At the
>>> same time, it's not a big deal to maintain the support Rami made in
>>> libX11. So why not?
>> Doesn't sound like you agree with me at all.  I just said why not, I'm
>> not going to repeat it.
> well, as you can see above ("I do agree with Julien in the sense"), I 
> partially agreed with you. Nothing to worry here :)
>> I understand what you're trying to solve, I
>> disagree that an xlib configure option is the way to go.
> cool that you understand. So could you suggest and recommend another 
> better way for everyone then?
>     Tiago

Would it be possible to guard against misbehaving applications by making 
it possible to configure libX11 with a dummy mutex?

typedef int dummy_mutex;

void lock(int *m) { assert(++(*m) == 1); };
void unlock(int *m) { *m = 0 };

It's not perfect but I guess it would be better than crashing in some 
random place in libX11.

-- Rami

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