调用c函数时出现分段错误

Question

I create a static library (name it myStaticLib) containing the c_mainwrapper. If I create a test-application I can call the function MainControllerInitiate(); without any problem.

When I create a shared library using myStaticLib and the c_wrapper I can call connectCreate(); without any problem. But when I try to call MainControllerInitiate(); I get a Segmentation fault.

Files:
c_mainwrapper.h

(...)
typedef void* MainController_p;
extern MainController_p (*createMainController)()

#ifdef __cplusplus
#define EXTERNC extern "C"
#else
#define EXTERNC
#endif

EXTERNC void MainControllerInitiate();
(...)

#undef EXTERNC
(...)

c_mainwrapper.cpp

(...)
MainController_p (*createMainController)() = NULL;
(...)
void MainControllerInitiate()
{
    if (createMainController != NULL)
    {
        createMainController();
    }
}
(...)

c_wrapper.h

(...)
#include <c_mainwrapper.h>

#ifdef __cplusplus
#define EXTERNC extern "C"
#else
#define EXTERNC
#endif

EXTERNC void connectCreate();
(...)

#undef EXTERNC
(...)

c_wrapper.cpp

(...)
MainController_p createController()
{
    return new MainController();
}

void connectCreate()
{
    createMainController = &createController;
}
(...)

Edit:
The failing test-application is just:

#include <c_wrapper>

int main(int argc, char *argv[])
{
    connectCreate();
    MainControllerInitiate(); // here the Segmentation fault occures

    return 0;
}

Edit2: Added the missing createMainController = NULL

Answer 1

found the problem by myselfe:

nobody asked for project files (tag qt). I compiled the static library as debug AND release. and in the shared library project-file I wrote:

CONFIG(release : debug|release)
{
    unix:!macx: LIBS += -L../../Build_Directory/x86/Release/myStaticLib \
    -lmyStaticLib
}
CONFIG(debug: debug|release)
{
    unix:!macx: LIBS += -L../../Build_Directory/x86/Debug/myStaticLib \
    -lmyStaticLib
}

The problem is, i used the wrong syntax. I has to be

CONFIG(release, debug|release){

and not

CONFIG(release : debug|release)
{

so I linked the shared library against the release version of the static library everytime. The error in the shared library was forced by myself. But i thought i would use the debug-version of the static library and could step through the code til the error.

conclusion: link against library debug-version if you want to step through the library code and check the make-files