• Gary Willoughby (3/3) Dec 21 2013 When porting C headers which include function declarations with
• Alexandr Druzhinin (4/7) Dec 21 2013 C vs D
• Gary Willoughby (6/15) Dec 22 2013 Thanks, that makes sense. But how would i port this parameter:
• Gary Willoughby (5/6) Dec 22 2013 and these:
• Benjamin Thaut (19/24) Dec 22 2013 In C/C++ the const always applies to whatever is left of it. If there is...
• Gary Willoughby (5/33) Dec 22 2013 Ah right, so:
• Benjamin Thaut (2/6) Dec 22 2013 Yes
• Gary Willoughby (3/12) Dec 22 2013 Great thanks! I thought i had a pretty good handle on C but
• Benjamin Thaut (20/33) Dec 22 2013 Yes, its sometimes really astonishing in what ways C-features can be
• Alexandr Druzhinin (9/16) Dec 22 2013 Yes, the last line should be

"Gary Willoughby" <dev nomad.so> writes:

When porting C headers which include function declarations with 
using char* types. Is it best to use const char* or const(char)* 
as the type in the D declaration?

Alexandr Druzhinin <drug2004 bk.ru> writes:

22.12.2013 07:47, Gary Willoughby пишет:
 When porting C headers which include function declarations with using
 char* types. Is it best to use const char* or const(char)* as the type
 in the D declaration?

C vs D
const char* == const(char)*
const char const* == const char*

"Gary Willoughby" <dev nomad.so> writes:

On Sunday, 22 December 2013 at 04:06:05 UTC, Alexandr Druzhinin 
wrote:
 22.12.2013 07:47, Gary Willoughby пишет:
 When porting C headers which include function declarations 
 with using
 char* types. Is it best to use const char* or const(char)* as 
 the type
 in the D declaration?

 C vs D
 const char* == const(char)*
 const char const* == const char*

Thanks, that makes sense. But how would i port this parameter:

struct Tcl_Obj * CONST * objv

Maybe like this?:

const Tcl_Obj[]* objv

"Gary Willoughby" <dev nomad.so> writes:

On Sunday, 22 December 2013 at 15:49:43 UTC, Gary Willoughby 
wrote:

 Thanks, that makes sense. But how would i port this parameter:

and these:

CONST84 char **tablePtr = ?
CONST84 char ***argvPtr = ?

Benjamin Thaut <code benjamin-thaut.de> writes:

Am 22.12.2013 17:02, schrieb Gary Willoughby:
 On Sunday, 22 December 2013 at 15:49:43 UTC, Gary Willoughby wrote:

 Thanks, that makes sense. But how would i port this parameter:

 and these:

 CONST84 char **tablePtr = ?
 CONST84 char ***argvPtr = ?

In C/C++ the const always applies to whatever is left of it. If there is 
nothing left of it, it applies to what is right to it.

So
"const char**" is equivalent to "char const **". That means the only 
part that is const is the char. In D const applies to whatever is inside 
the parantheses.
So the equivalent in D would be

const(char)** and const(char)***

If you have something like the following in C:

const char * const

the D equivalent would be
const(char*)

Note that the star is included in the parantheses here, because the 
pointer is const to, not only the data it points to.

the D type: const(char**) would be equivalent to C: char const * const * 
const. (But you won't ever needs this)

Kind Regards
Benjamin Thaut

"Gary Willoughby" <dev nomad.so> writes:

On Sunday, 22 December 2013 at 16:45:15 UTC, Benjamin Thaut wrote:
 Am 22.12.2013 17:02, schrieb Gary Willoughby:
 On Sunday, 22 December 2013 at 15:49:43 UTC, Gary Willoughby 
 wrote:

 Thanks, that makes sense. But how would i port this parameter:

 and these:

 CONST84 char **tablePtr = ?
 CONST84 char ***argvPtr = ?

 In C/C++ the const always applies to whatever is left of it. If 
 there is nothing left of it, it applies to what is right to it.

 So
 "const char**" is equivalent to "char const **". That means the 
 only part that is const is the char. In D const applies to 
 whatever is inside the parantheses.
 So the equivalent in D would be

 const(char)** and const(char)***

 If you have something like the following in C:

 const char * const

 the D equivalent would be
 const(char*)

 Note that the star is included in the parantheses here, because 
 the pointer is const to, not only the data it points to.

 the D type: const(char**) would be equivalent to C: char const 
 * const * const. (But you won't ever needs this)

 Kind Regards
 Benjamin Thaut

Ah right, so:

struct Tcl_Obj * CONST * objv

would be:

const(Tcl_Obj*)* objv  or  const(Tcl_Obj*)[] objv

Benjamin Thaut <code benjamin-thaut.de> writes:

Am 22.12.2013 18:39, schrieb Gary Willoughby:
 Ah right, so:

 struct Tcl_Obj * CONST * objv

 would be:

 const(Tcl_Obj*)* objv  or  const(Tcl_Obj*)[] objv

Yes

"Gary Willoughby" <dev nomad.so> writes:

On Sunday, 22 December 2013 at 18:28:43 UTC, Benjamin Thaut wrote:
 Am 22.12.2013 18:39, schrieb Gary Willoughby:
 Ah right, so:

 struct Tcl_Obj * CONST * objv

 would be:

 const(Tcl_Obj*)* objv  or  const(Tcl_Obj*)[] objv

 Yes

Great thanks! I thought i had a pretty good handle on C but 
porting some headers makes me scratch my head.

Benjamin Thaut <code benjamin-thaut.de> writes:

Am 22.12.2013 20:34, schrieb Gary Willoughby:
 On Sunday, 22 December 2013 at 18:28:43 UTC, Benjamin Thaut wrote:
 Am 22.12.2013 18:39, schrieb Gary Willoughby:
 Ah right, so:

 struct Tcl_Obj * CONST * objv

 would be:

 const(Tcl_Obj*)* objv  or  const(Tcl_Obj*)[] objv

 Yes

 Great thanks! I thought i had a pretty good handle on C but porting some
 headers makes me scratch my head.

Yes, its sometimes really astonishing in what ways C-features can be 
abused. I very recently sumbled apon this:

void (*callbackFunc)(GtkWidget* widget, void* userData);

void registerCallback(callbackFunc func);

void userCallback(GtkEntry* entry)
{
   ...
}

void someFunc()
{
   registerCallback((callbackFunc)&userCallback);
}

Note that the signature of the funciton does not match at all. The first 
parameter is "casted" automatically to a different data type, which only 
works because pointers always have the same size and the second paramter 
is omitted completely. This only works because of the C calling 
convetion. C can be a strange land ;-)

Kind Regards
Benjamin Thaut

Alexandr Druzhinin <drug2004 bk.ru> writes:

22.12.2013 11:06, Alexandr Druzhinin пишет:
 22.12.2013 07:47, Gary Willoughby пишет:
 When porting C headers which include function declarations with using
 char* types. Is it best to use const char* or const(char)* as the type
 in the D declaration?

 C vs D
 const char* == const(char)*
 const char const* == const char*

Yes, the last line should be
const char * const == const char*
thanks to Benjamin

IIRC in D qualificator is applied to the right part of statement if 
there is no the parantheses and to part inside the parantheses if they 
exists. Important thing is that in D qualificators are transitive. It 
makes type system more robust (from POV immutability), but doesn't 
complete it, sadly.