Mail Archives: cygwin/2005/01/18/08:21:21
Hi,
The way symbol names are built in dll differs if they are related to c
call convention or to c++ call, and that could be your problem. When
compiling hello.c with gcc, your exported symbol corresponds to C
calling convention.
When compiling dll with g++, you should declare your exported function
as 'extern "C"' in hello.c.
David Marteau
svoboda AT cs DOT cmu DOT edu wrote:
>I've been trying to build a DLL using g++, and given the problems I was
>having, I decided to try a 'toy' example, which is available at:
> http://cygwin.com/cygwin-ug-net/dll.html
>I tweaked the two files around thusly:
>
>
>hello.C:
>-----
>#include <stdio.h>
>int hello() { printf("Hello World\n");}
>-----
>
>main.C:
>-----
>#include <stdio.h>
>typedef void (*fn_type)();
>
>extern "C" {
> int dlopen(char*);
> int dlsym( int, char*);
>}
>
>int main() {
> int handle = 0;
> fn_type fn = 0;
> if ((handle = dlopen( "hello.dll")) == 0) {
> printf( "Cannot open hello.dll\n");
> }
> if ((fn = (fn_type) dlsym( handle, "hello")) == 0) {
> printf( "Cannot open hello()\n");
> }
> fn();
>}
>-----
>
>This way, hello.C is a valid C or C++ application, and main.C is a
>valid C++ application. I build main.exe by:
>
> g++ -o main main.C
>
>If I build hello.dll this way, it works:
>
> gcc -shared -o hello.dll hello.C
> ./main
> Hello world!
>
>But if I build hello.dll this way, it doesn't work:
>
> g++ -shared -o hello.dll hello.C
> ./main
> bash: [2084: 2] testaddr: Inappropriate ioctl for device
>
>Why? What am I doing wrong?
>
>~David Svoboda
>
>
>
--
Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
Problem reports: http://cygwin.com/problems.html
Documentation: http://cygwin.com/docs.html
FAQ: http://cygwin.com/faq/
- Raw text -