Re: [Mingw-users] Problems with gcc 3.1 and dll's

[Luke D. <cod...@ho...>]

----- Original Message -----
From: "Oscar Fuentes" <of...@wa...>
To: <min...@li...>
Sent: Saturday, May 18, 2002 4:22 PM
Subject: Re: [Mingw-users] Problems with gcc 3.1 and dll's


>
> Also, as reported on previous msgs on this thread, in all cases
> wxWindows 2.2.9 is unusable as a dll. I guess the culprit here /seems/
> gcc, as at least MinGW 1.1 builds a valid dll.
>

I have verified that the following code is not compiled correctly with Mingw
gcc 3.1:

/////
class __attribute__((dllexport)) Foo
{
        void func();
};

class Bar
{
        friend class Foo;
};

void Foo::func()
{
}
/////

Compiling with "gcc -S export.cpp", the output is:

 .file "export.cpp"
 .text
 .align 2
.globl __ZN3Foo4funcEv
 .def __ZN3Foo4funcEv; .scl 2; .type 32; .endef
__ZN3Foo4funcEv:
LFB1:
 pushl %ebp
LCFI0:
 movl %esp, %ebp
LCFI1:
 popl %ebp
 ret
LFE1:


If the "friend" declaration is removed, the function is correctly exported:

 .section .drectve

 .ascii " -export:_ZN3Foo4funcEv"

In wxWindows this causes the wxObject constructor to not be exported, while
most classes are exported properly. However, some members of wxObject ARE
exported, but I don't have a test case yet to demonstrate which ones.

Luke