digitalmars.D.learn - Interfacing to C. extern (C) variables
- "Alex_Dovhal" <alex_dovhal yahoo.com> Jun 26 2011
- Robert Clipsham <robert octarineparrot.com> Jun 26 2011
- "Alex_Dovhal" <alex_dovhal yahoo.com> Jun 26 2011
- Jimmy Cao <jcao219 gmail.com> Jun 26 2011
- "Alex_Dovhal" <alex_dovhal yahoo.com> Jun 26 2011
Hi. I try to interface D module with C one. See:
* file test.c:
#include <stdio.h>
int c_var;
int func()
{
c_var = 1234;
printf("In C\n");
printf("c_var = %d\n", c_var);
printf("&c_var = %x\n", &c_var);
return 0;
}
* file unit.d:
module unit;
import std.stdio;
extern(C){
int c_var;
int func();
}
void main()
{
func();
writeln("In D");
writefln("c_var = %d", c_var);
writefln("&c_var = %x", &c_var);
}
And compile:
dmc -c test.c
dmd unit.d test.obj
I'd like to call C functions and use C variables in D module.
D calls C functions just fine, but how can I use C variables?
This program outputs:
In C
c_var = 1234
&c_var = 45d004
In D
c_var = 0
&c_var = 14298c
Jun 26 2011
On 26/06/2011 20:54, Alex_Dovhal wrote:I'd like to call C functions and use C variables in D module. D calls C functions just fine, but how can I use C variables?
extern(C) extern int myCVar; -- Robert http://octarineparrot.com/
Jun 26 2011
"Alex_Dovhal" <alex_dovhal yahoo.com> "Robert Clipsham" <robert octarineparrot.com> wrote:On 26/06/2011 20:54, Alex_Dovhal wrote:I'd like to call C functions and use C variables in D module. D calls C functions just fine, but how can I use C variables?
extern(C) extern int myCVar;
Thanks for answer. I've already tried that, it doesn't work for some reason: * file unit2.d: module unit; import std.stdio; extern(C) int func(); extern(C) extern int c_var; void main() { func(); writeln("In D"); writefln("c_var = %d", c_var); writefln("&c_var = %x", &c_var); } Result: In C c_var = 1234 &c_var = 470200 In D object.Error: Access Violation ---------------- 426DA4 426C1B 405BEB 4057E7 451099 ---------------- Found workaround, but it's extreme hack: *file test.c #include <stdio.h> int c_var; //int* ref_c_var() //{ // return &c_var; //} #define REF_DECL(type, name) type* ref_ ## name () {return &name;} REF_DECL(int, c_var) int func() { c_var = 1234; printf("In C\n"); printf("c_var = %d\n", c_var); printf("&c_var = %x\n", &c_var); return 0; } *file: unit1.d: module unit; import std.stdio; extern(C) int func(); string C_VAR(string type, string name) { return "extern (C) "~ type ~ "* ref_" ~ name ~ "();"~ " " ~ "ref " ~ type ~ " " ~ name ~"(){return *ref_"~name~"();}"; } mixin(C_VAR("int", "c_var")); void main() { func(); writeln("In D"); writefln("c_var = %d", c_var); writefln("&c_var = %x", &c_var); }
Jun 26 2011
--0016363b8cecb9ba4804a6a5819e Content-Type: text/plain; charset=ISO-8859-1 On Sun, Jun 26, 2011 at 5:00 PM, Alex_Dovhal <alex_dovhal yahoo.com> wrote:"Robert Clipsham" <robert octarineparrot.com> wrote:On 26/06/2011 20:54, Alex_Dovhal wrote:I'd like to call C functions and use C variables in D module. D calls C functions just fine, but how can I use C variables?
extern(C) extern int myCVar;
Thanks for answer. I've already tried that, it doesn't work for some reason: * file unit2.d: module unit; import std.stdio; extern(C) int func(); extern(C) extern int c_var; void main() { func(); writeln("In D"); writefln("c_var = %d", c_var); writefln("&c_var = %x", &c_var); } Result: In C c_var = 1234 &c_var = 470200 In D object.Error: Access Violation ---------------- 426DA4 426C1B 405BEB 4057E7 451099 ---------------- Found workaround, but it's extreme hack: *file test.c #include <stdio.h> int c_var; //int* ref_c_var() //{ // return &c_var; //} #define REF_DECL(type, name) type* ref_ ## name () {return &name;} REF_DECL(int, c_var) int func() { c_var = 1234; printf("In C\n"); printf("c_var = %d\n", c_var); printf("&c_var = %x\n", &c_var); return 0; } *file: unit1.d: module unit; import std.stdio; extern(C) int func(); string C_VAR(string type, string name) { return "extern (C) "~ type ~ "* ref_" ~ name ~ "();"~ " " ~ "ref " ~ type ~ " " ~ name ~"(){return *ref_"~name~"();}"; } mixin(C_VAR("int", "c_var")); void main() { func(); writeln("In D"); writefln("c_var = %d", c_var); writefln("&c_var = %x", &c_var); }
It works for me like this: extern(C){ __gshared int c_var; int func(); } --0016363b8cecb9ba4804a6a5819e Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On Sun, Jun 26, 2011 at 5:00 PM, Alex_Dovhal <span dir=3D"ltr"><<a href= =3D"mailto:alex_dovhal yahoo.com">alex_dovhal yahoo.com</a>></span> wrot= e:<br><div class=3D"gmail_quote"><blockquote class=3D"gmail_quote" style=3D= "margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"> <div class=3D"im">"Robert Clipsham" <<a href=3D"mailto:robert = octarineparrot.com">robert octarineparrot.com</a>> wrote:<br> > On 26/06/2011 20:54, Alex_Dovhal wrote:<br> >> I'd like to call C functions and use C variables in D module.<= br> >> D calls C functions just fine, but how can I use C variables?<br> ><br> > extern(C) extern int myCVar;<br> <br> </div>Thanks for answer. I've already tried that, it doesn't work f= or some reason:<br> <br> * file unit2.d:<br> <div class=3D"im">module unit;<br> import std.stdio;<br> </div>extern(C) int func();<br> <div class=3D"im">extern(C) extern int c_var;<br> <br> </div><div class=3D"im">void main()<br> {<br> =A0 =A0func();<br> =A0 =A0writeln("In D");<br> =A0 =A0writefln("c_var =3D %d", c_var);<br> =A0 =A0writefln("&c_var =3D %x", &c_var);<br> }<br> <br> </div>Result:<br> <div class=3D"im">In C<br> c_var =3D 1234<br> </div>&c_var =3D 470200<br> In D<br> object.Error: Access Violation<br> ----------------<br> 426DA4<br> 426C1B<br> 405BEB<br> 4057E7<br> 451099<br> ----------------<br> <br> <br> Found workaround, but it's extreme hack:<br> <br> *file test.c<br> <div class=3D"im">#include <stdio.h><br> int c_var;<br> </div>//int* ref_c_var()<br> //{<br> // =A0 =A0return &c_var;<br> //}<br> <br> #define REF_DECL(type, name) type* ref_ ## name () {return &name;}<br> <br> REF_DECL(int, c_var)<br> <div class=3D"im"><br> int func()<br> {<br> =A0 =A0c_var =3D 1234;<br> =A0 =A0printf("In C\n");<br> =A0 =A0printf("c_var =3D %d\n", c_var);<br> =A0 =A0printf("&c_var =3D %x\n", &c_var);<br> =A0 =A0return 0;<br> }<br> <br> </div>*file: unit1.d:<br> <div class=3D"im">module unit;<br> import std.stdio;<br> <br> </div>extern(C) int func();<br> <br> string C_VAR(string type, string name)<br> {<br> =A0 =A0return<br> =A0 =A0 =A0 =A0"extern (C) "~ type ~ "* ref_" ~ name ~= "();"~<br> =A0 =A0 =A0 =A0" " ~ "ref " ~ type ~ " " ~ n= ame ~"(){return *ref_"~name~"();}";<br> }<br> <br> mixin(C_VAR("int", "c_var"));<br> <div><div></div><div class=3D"h5"><br> void main()<br> {<br> =A0 =A0func();<br> =A0 =A0writeln("In D");<br> =A0 =A0writefln("c_var =3D %d", c_var);<br> =A0 =A0writefln("&c_var =3D %x", &c_var);<br> }<br> <br> <br> </div></div></blockquote></div><br><div><br></div><div>It works for me like= this:</div><div><br></div><blockquote class=3D"webkit-indent-blockquote" s= tyle=3D"margin: 0 0 0 40px; border: none; padding: 0px;"><div><div>extern(C= ){</div> <div>=A0 =A0__gshared int c_var;</div><div>=A0 =A0int func();</div><div>}</= div></div></blockquote> --0016363b8cecb9ba4804a6a5819e--
Jun 26 2011
"Jimmy Cao" <jcao219 gmail.com> wrote:It works for me like this: extern(C){ __gshared int c_var; int func(); }
Thanks.
Jun 26 2011