X11 XSynchronize() definition in D

2013-08-06 Thread andrea9940 
Hi, I'm working with the X11 library available from 
https://github.com/D-Programming-Deimos/libX11
If I try to call XSynchronize(display, True) the compilation 
fails with Error: function deimos.X11.Xlib.XSynchronize 
(_XDisplay*) is not callable using argument types (_XDisplay*, 
int)


I am sure the arguments are correct (see http://goo.gl/8Hzn8s for 
example) so I think there is a conversion problem between the C 
and D definition of the function:


--- Xlib.h
extern int (*XSynchronize(
Display*/* display */,
Bool/* onoff */
))(
Display*/* display */
);

--- Xlib.d
extern int function(
Display*/* display */,
Bool/* onoff */
)XSynchronize(
Display*/* display */
);


Also I can't understand why the C version is not extern int 
XSynchronize(Display*,

Bool); which would be the simplest definition.

Re: X11 XSynchronize() definition in D

2013-08-06 Thread bearophile 

andrea9940:


extern int function(
Display*/* display */,
Bool/* onoff */
)XSynchronize(
Display*/* display */
);


Try extern(C)?

Bye,
bearophile

Re: X11 XSynchronize() definition in D

2013-08-06 Thread andrea9940 

On Tuesday, 6 August 2013 at 08:21:26 UTC, bearophile wrote:

Try extern(C)?


It's not a linkage error, it's a syntax one

Re: X11 XSynchronize() definition in D

2013-08-06 Thread Ali Çehreli 

On 08/06/2013 01:01 AM, andrea9940 wrote:

 Hi, I'm working with the X11 library available from
 https://github.com/D-Programming-Deimos/libX11
 If I try to call XSynchronize(display, True) the compilation fails with
 Error: function deimos.X11.Xlib.XSynchronize (_XDisplay*) is not
 callable using argument types (_XDisplay*, int)

 I am sure the arguments are correct (see http://goo.gl/8Hzn8s for
 example) so I think there is a conversion problem between the C and D
 definition of the function:

 --- Xlib.h
 extern int (*XSynchronize(
  Display*/* display */,
  Bool/* onoff */
 ))(
  Display*/* display */
 );

I have written the following stubs for C:

typedef void Display;
typedef int Bool;

extern int (*XSynchronize(
Display*/* display */,
Bool/* onoff */
))(
Display*/* display */
);

typedef int(*PreviousAfterFunction)(Display*);

int previous_after_foo(Display* display)
{
return 0;
}

PreviousAfterFunction XSynchronize(Display* display, Bool onoff)
{
return previous_after_foo;
}

int main()
{
int (*paf)(Display*) = XSynchronize(0, 1);
paf(0);
}

And then I have written the direct translation in D, which works as well:

struct Display
{}

alias PreviousAfterFunction = int function(Display*);

int previousAfterFoo(Display *)
{
return 0;
}

PreviousAfterFunction XSynchronize(Display*, bool)
{
return previousAfterFoo;
}

void main()
{
PreviousAfterFunction paf = XSynchronize(null, 1);
paf(null);
}

 --- Xlib.d
 extern int function(
  Display*/* display */,
  Bool/* onoff */
 )XSynchronize(
  Display*/* display */
 );

It looks like Xlib.d got it backwards: XSynchronize takes two parameters 
and returns a function pointer that takes a single parameter. It should 
be the following:


int function(Display*) XSynchronize(Display*, bool);

 Also I can't understand why the C version is not extern int
 XSynchronize(Display*,
  Bool); which would be the simplest definition.

That's different. That would be a function taking two parameters and 
returning int. However, XSynchronize takes two parameters and return a 
function pointer (that takes one parameter and returns an int).


Ali

Re: X11 XSynchronize() definition in D

2013-08-06 Thread David 
 struct Display
 {}

D supports opaque structs/pointers

struct Display;

Now Display has to be used as pointer only or the compiler complains
e.g. about

Display display;

Re: X11 XSynchronize() definition in D

2013-08-06 Thread andrea9940 

@Ali Çehreli
Thank you for the explanation. I'll send a pull request to fix 
Xlib.d

Re: X11 XSynchronize() definition in D

2013-08-06 Thread Ali Çehreli 

On 08/06/2013 03:22 AM, David wrote: struct Display
 {}

 D supports opaque structs/pointers

 struct Display;

 Now Display has to be used as pointer only or the compiler complains
 e.g. about

 Display display;

Yes and I am sure that is how Xlib.d has it.

However, remembering a limitation that we have discovered a couple of 
weeks ago, I intentionally did not make it opaque, in case somebody 
would try toString() on it:


  http://forum.dlang.org/post/ksc2ln$f1i$1...@digitalmars.com

I have been to lazy to bring this topic up on the main newsgroup before 
opening an enhancement request.


Ali

Re: X11 XSynchronize() definition in D

2013-08-06 Thread Ali Çehreli 

On 08/06/2013 08:46 AM, Ali Çehreli wrote:

 On 08/06/2013 03:22 AM, David wrote: struct Display
   {}
  
   D supports opaque structs/pointers
  
   struct Display;
  
   Now Display has to be used as pointer only or the compiler complains
   e.g. about
  
   Display display;

 Yes and I am sure that is how Xlib.d has it.

 However, remembering a limitation that we have discovered a couple of
 weeks ago, I intentionally did not make it opaque, in case somebody
 would try toString() on it:

I am confused and being confusing... I think nobody should apply 
toString() on an opaque type as it is supposed to dereference the actual 
object.


http://forum.dlang.org/post/ksc2ln$f1i$1...@digitalmars.com

I will continue on that thread.

Ali