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digitalmars.D.learn - using pragma to link to gcc-compiled c library

reply "Felix Klein" <coogabooga hotmail.com> writes:
hi,

i'm having a hard time linking a c function into d.  i've looked 
at many posts about this, but can't seem to get it to work.  at 
the moment i'm trying to use pragma in the d source to help dmd 
find the function.  unfortunately the linker can't find it.

felix mojo:~/d/misc$ cat ctest.d
import std.stdio;
pragma(lib, "/home/felix/d/misc/libcadder.a");

void
main()
{

   extern (C) int addem (int, int);

   int a=2, b=3;

   int c = addem(a,b);

   writeln("c=",c);
}
felix mojo:~/d/misc$ cat cadder.c
int
addem(int a, int b)
{
   return (a+b);
}
felix mojo:~/d/misc$ gcc -c cadder.c -o cadder.o
felix mojo:~/d/misc$ ar rcs libcadder.a cadder.o
felix mojo:~/d/misc$ dmd ctest.d
ctest.o: In function `_Dmain':
ctest.d:(.text._Dmain+0x18): undefined reference to 
`_D5ctest4mainFZv5addemMUiiZi'
collect2: ld returned 1 exit status
--- errorlevel 1
felix mojo:~/d/misc$
Jun 05 2012
parent reply Artur Skawina <art.08.09 gmail.com> writes:
On 06/06/12 02:33, Felix Klein wrote:

 hi,
 
 i'm having a hard time linking a c function into d.  i've looked at many posts
about this, but can't seem to get it to work.  at the moment i'm trying to use
pragma in the d source to help dmd find the function.  unfortunately the linker
can't find it.
 
 felix mojo:~/d/misc$ cat ctest.d
 import std.stdio;
 pragma(lib, "/home/felix/d/misc/libcadder.a");
 
 void
 main()
 {
 
   extern (C) int addem (int, int);


Move the proto out of main() into the module scope - as is,
it's treated as a nested function and gets its name mangled.

artur
Jun 05 2012
parent "Felix Klein" <coogabooga hotmail.com> writes:
 void
 main()
 {
 
   extern (C) int addem (int, int);


 Move the proto out of main() into the module scope - as is,
 it's treated as a nested function and gets its name mangled.

 artur


that was exactly the right thing to do!  thanks for your prompt 
help.

-fk
Jun 05 2012