• llee (2/2) Jul 02 2008 I'm writing an application that is compiled against several object ...
• BCS (13/22) Jul 02 2008 put "extern(C) FILE* yyin;" in another d file and import it but don't li...
• llee (2/34) Jul 02 2008 it works.
• Frank Benoit (4/23) Jul 02 2008 you can link the file if you use

llee <llee goucher.edu> writes:

     I'm writing an application that is compiled against several object files
that have been coded in c. These files define a variable named yyin that has
the following prototype: FILE* yyin.
     I need to access this variable from my d code. I tried referencing the
variable using the following statement: yyin = fopen (&fname [0], &fmode [0]);,
but the compiler returned an error stating that yyin was undefined. I tried
including the following extern (C) statement: extern (C) FILE* yyin;, but the
linker complained that yyin was defined multiple times.\

BCS <ao pathlink.com> writes:

Reply to llee,

 I'm writing an application that is compiled against several
 object files that have been coded in c. These files define a variable
 named yyin that has the following prototype: FILE* yyin.
 I need to access this variable from my d code. I tried
 referencing the variable using the following statement: yyin = fopen
 (&fname [0], &fmode [0]);, but the compiler returned an error stating
 that yyin was undefined. I tried including the following extern (C)
 statement: extern (C) FILE* yyin;, but the linker complained that yyin
 was defined multiple times.\

put "extern(C) FILE* yyin;" in another d file and import it but don't link 
it in. I think that will work


somefile.c
extern FILE* yyin;

header.d:
extern(C) FILE* yyin;

use.d
import header;
void main(){writef("%x\n", cast(void*)yyin);}


gcc -c somefile.c;
dmd -c use.d;
dmd  use.o somefile.o

llee <llee goucher.edu> writes:

BCS Wrote:

 Reply to llee,
 
 I'm writing an application that is compiled against several
 object files that have been coded in c. These files define a variable
 named yyin that has the following prototype: FILE* yyin.
 I need to access this variable from my d code. I tried
 referencing the variable using the following statement: yyin = fopen
 (&fname [0], &fmode [0]);, but the compiler returned an error stating
 that yyin was undefined. I tried including the following extern (C)
 statement: extern (C) FILE* yyin;, but the linker complained that yyin
 was defined multiple times.\

 
 put "extern(C) FILE* yyin;" in another d file and import it but don't link 
 it in. I think that will work
 
 
 somefile.c
 extern FILE* yyin;
 
 header.d:
 extern(C) FILE* yyin;
 
 use.d
 import header;
 void main(){writef("%x\n", cast(void*)yyin);}
 
 
 gcc -c somefile.c;
 dmd -c use.d;
 dmd  use.o somefile.o
 
 

it works. 

Frank Benoit <keinfarbton googlemail.com> writes:

llee schrieb:
 BCS Wrote:
 somefile.c
 extern FILE* yyin;

 header.d:
 extern(C) FILE* yyin;

 use.d
 import header;
 void main(){writef("%x\n", cast(void*)yyin);}


 gcc -c somefile.c;
 dmd -c use.d;
 dmd  use.o somefile.o

 it works. 
 

you can link the file if you use

extern extern(C) FILE* yyin;

a dangerous pitfall to forget the first extern.