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
[EMAIL PROTECTED] 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
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