I can't seem to get this to work right:

gcc -m32 -shared -fPIC Test.cpp -o libTest.so
g++ -m32 test_c.cpp -L. -lTest -o test_c
wine htod.exe Test.h Test.d
dmd test_d.d Test.d -L-L. -L-lTest -oftest_d
test_d.o: In function `_Dmain':
Test.d:(.text._Dmain+0x20): undefined reference to `increment'
collect2: ld returned 1 exit status
--- errorlevel 1
make: *** [test_d] Error 1

The resulting test_c binary from g++ works as intented (With either LD_LIBRARY_PATH="." or LD_RUN_PATH="."):
$ ./test_c
Count = 0
Count = 1
$ ldd test_c
	linux-gate.so.1 =>  (0x00ad1000)
	libTest.so (0x005b9000)
	libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x4970f000)
	libm.so.6 => /lib/libm.so.6 (0x4955b000)
	libgcc_s.so.1 => /lib/libgcc_s.so.1 (0x49587000)
	libc.so.6 => /lib/libc.so.6 (0x493ab000)
	/lib/ld-linux.so.2 (0x4938a000)

Any ideas on what I'm doing wrong here?

I've dropbox-ed the code if it's helpful.
http://dl.dropbox.com/u/12135920/kai_test_c_interface.zip

-Kai Meyer

Kai Meyer Wrote:

> I can't seem to get this to work right:
> 
> gcc -m32 -shared -fPIC Test.cpp -o libTest.so
> g++ -m32 test_c.cpp -L. -lTest -o test_c
> wine htod.exe Test.h Test.d
> dmd test_d.d Test.d -L-L. -L-lTest -oftest_d
> test_d.o: In function `_Dmain':
> Test.d:(.text._Dmain+0x20): undefined reference to `increment'
> collect2: ld returned 1 exit status
> --- errorlevel 1
> make: *** [test_d] Error 1
> 
> The resulting test_c binary from g++ works as intented (With either
> LD_LIBRARY_PATH="." or LD_RUN_PATH="."):
> $ ./test_c
> Count = 0
> Count = 1
> $ ldd test_c
> 	linux-gate.so.1 =>  (0x00ad1000)
> 	libTest.so (0x005b9000)

try non-shared libTest, dmd prefers single executable compilations.

On 03/05/2011 06:24 AM, Kagamin wrote:
> Kai Meyer Wrote:
>
>> I can't seem to get this to work right:
>>
>> gcc -m32 -shared -fPIC Test.cpp -o libTest.so
>> g++ -m32 test_c.cpp -L. -lTest -o test_c
>> wine htod.exe Test.h Test.d
>> dmd test_d.d Test.d -L-L. -L-lTest -oftest_d
>> test_d.o: In function `_Dmain':
>> Test.d:(.text._Dmain+0x20): undefined reference to `increment'
>> collect2: ld returned 1 exit status
>> --- errorlevel 1
>> make: *** [test_d] Error 1
>>
>> The resulting test_c binary from g++ works as intented (With either
>> LD_LIBRARY_PATH="." or LD_RUN_PATH="."):
>> $ ./test_c
>> Count = 0
>> Count = 1
>> $ ldd test_c
>> 	linux-gate.so.1 =>   (0x00ad1000)
>> 	libTest.so (0x005b9000)
>
> try non-shared libTest, dmd prefers single executable compilations.

Is that the only option? I know it's possible to link to external c libraries, and I'd like to learn how.

On 03/07/2011 08:57 AM, Kai Meyer wrote:
> On 03/05/2011 06:24 AM, Kagamin wrote:
>> Kai Meyer Wrote:
>>
>>> I can't seem to get this to work right:
>>>
>>> gcc -m32 -shared -fPIC Test.cpp -o libTest.so
>>> g++ -m32 test_c.cpp -L. -lTest -o test_c
>>> wine htod.exe Test.h Test.d
>>> dmd test_d.d Test.d -L-L. -L-lTest -oftest_d
>>> test_d.o: In function `_Dmain':
>>> Test.d:(.text._Dmain+0x20): undefined reference to `increment'
>>> collect2: ld returned 1 exit status
>>> --- errorlevel 1
>>> make: *** [test_d] Error 1
>>>
>>> The resulting test_c binary from g++ works as intented (With either
>>> LD_LIBRARY_PATH="." or LD_RUN_PATH="."):
>>> $ ./test_c
>>> Count = 0
>>> Count = 1
>>> $ ldd test_c
>>> linux-gate.so.1 => (0x00ad1000)
>>> libTest.so (0x005b9000)
>>
>> try non-shared libTest, dmd prefers single executable compilations.
>
> Is that the only option? I know it's possible to link to external c
> libraries, and I'd like to learn how.

So I monkeyed around a little bit, and found out that if I change "extern (C)" to "extern (C++)", the library links correctly and the program runs.

That lead me to believe that if I added the "-cpp" option to htod.exe, it would generate extern(C++) functions. But I got a blank Test.d file doing it that way.

So, gcc created a libTest.so with a function in it, and dmd only finds the function with extern(C++) and not with extern(C).

Now I'm just confused, yet pleased something worked.

-Kai Meyer