Calling a D function from C

[Carlo]

On 12/11/2010 16:19, Michal Minich wrote:
> V Fri, 12 Nov 2010 16:14:30 +0100, Carlo wrote:
>
>> Sorry if I bother you again with this probably silly problem. Here is
>> the point. I want to call the D function "fun" from a .c file:
>>
>> \\file libforc.d
>> extern (C) int fun(int x,int y){
>>           return x;
>> }
>> \\EOF
>>
>> \\file ctest.c
>> #include<stdio.h>
>>
>> int fun(int,int);
>>
>> int main(int argc, char* argv[])
>> {
>>        printf("%d",fun(2,3));
>>
>>        return 0;
>> }
>> \\EOF
>>
>> This what I get trying to compile the .c file:
>>
>> $ dmd libforc.d -c
>> $ gcc libforc.o ctest.c -m32
>> libforc.o: In function `no symbol':
>> libforc.d:(.text+0x8): undefined reference to `_Dmodule_ref' collect2:
>> ld returned 1 exit status
>>
>> What did I miss?
>
> You probably need to include phobos library in gcc command line.
Actually there exist a library phobos2, but i think it's a D object 
file. Here is what I get:

carlo at carlo-laptop:~/d$ dmd -c libforc.d
carlo at carlo-laptop:~/d$ ar rcs libforc.a libforc.o
carlo at carlo-laptop:~/d$ gcc -L. -lforc -lphobos2 -m32 ctest.c
/tmp/ccpbEtKu.o: In function `main':
ctest.c:(.text+0x0): multiple definition of `main'
/usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib32/libphobos2.a(dmain2_503_1a5.o):src/rt/dmain2.d:(.text.main+0x0): 
first defined here
/usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib32/libphobos2.a(dmain2_503_1a5.o): 
In function `_D2rt6dmain24mainUiPPaZi7runMainMFZv':
src/rt/dmain2.d:(.text._D2rt6dmain24mainUiPPaZi7runMainMFZv+0x16): 
undefined reference to `_Dmain'
/usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib32/libphobos2.a(critical.o): 
In function `_STI_critical_init':
critical.c:(.text+0x43): undefined reference to `pthread_mutexattr_init'
critical.c:(.text+0x57): undefined reference to 
`pthread_mutexattr_settype'carlo at carlo-laptop:~/d$ dmd -c libforc.d
carlo at carlo-laptop:~/d$ ar rcs libforc.a libforc.o
carlo at carlo-laptop:~/d$ gcc -L. -lforc -lphobos2 -m32 ctest.c
/tmp/ccpbEtKu.o: In function `main':
ctest.c:(.text+0x0): multiple definition of `main'
/usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib32/libphobos2.a(dmain2_503_1a5.o):src/rt/dmain2.d:(.text.main+0x0): 
first defined here
/usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib32/libphobos2.a(dmain2_503_1a5.o): 
In function `_D2rt6dmain24mainUiPPaZi7runMainMFZv':
src/rt/dmain2.d:(.text._D2rt6dmain24mainUiPPaZi7runMainMFZv+0x16): 
undefined reference to `_Dmain'
/usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib32/libphobos2.a(critical.o): 
In function `_STI_critical_init':
critical.c:(.text+0x43): undefined reference to `pthread_mutexattr_init'
critical.c:(.text+0x57): undefined reference to `pthread_mutexattr_settype'
/usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib32/libphobos2.a(monitor.o): 
In function `_STD_monitor_staticdtor':
monitor.c:(.text+0x1dc): undefined reference to `pthread_mutexattr_destroy'
/usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib32/libphobos2.a(monitor.o): 
In function `_STI_monitor_staticctor':
monitor.c:(.text+0x1f9): undefined reference to `pthread_mutexattr_init'
monitor.c:(.text+0x20d): undefined reference to `pthread_mutexattr_settype'
/usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib32/libphobos2.a(thread_e7_258.o): 
In function `_D4core6thread6Thread6__dtorMFZv':
src/core/thread.d:(.text._D4core6thread6Thread6__dtorMFZv+0x17): 
undefined reference to `pthread_detach'
/usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib32/libphobos2.a(thread_e7_258.o): 
In function `_D4core6thread6Thread5startMFZv':
src/core/thread.d:(.text._D4core6thread6Thread5startMFZv+0x79): 
undefined reference to `pthread_attr_setstacksize'

/usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib32/libphobos2.a(monitor.o): 
In function `_STD_monitor_staticdtor':
monitor.c:(.text+0x1dc): undefined reference to `pthread_mutexattr_destroy'
/usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib32/libphobos2.a(monitor.o): 
In function `_STI_monitor_staticctor':
monitor.c:(.text+0x1f9): undefined reference to `pthread_mutexattr_init'
monitor.c:(.text+0x20d): undefined reference to `pthread_mutexattr_settype'
/usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib32/libphobos2.a(thread_e7_258.o): 
In function `_D4core6thread6Thread6__dtorMFZv':
src/core/thread.d:(.text._D4core6thread6Thread6__dtorMFZv+0x17): 
undefined reference to `pthread_detach'
/usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib32/libphobos2.a(thread_e7_258.o): 
In function `_D4core6thread6Thread5startMFZv':
src/core/thread.d:(.text._D4core6thread6Thread5startMFZv+0x79): 
undefined reference to `pthread_attr_setstacksize'
................................................