Security Check Stack overflow compiler GS option

[ForNow]

Hi I put my ownerdraw code in a C dll upon exiting it I got a Security check stack overflow. I turned the /GS complier option off looked to work fine under VS debugger. The Calling code is MFC C/C++ The DLL is in C Here is the MFC code

CMystatic::CMystatic()
{
width = 0;
mod = LoadLibrary(TEXT("C:\\SYSADATA\\SYSADATA\\x64\\Debug\\SYSADATA.DLL"));
drawptr = (fownerdraw)GetProcAddress(mod, "ownerdraw");
strsize.cx = 0;
strsize.cy = 0;
myexitparm = &exitparm;
}

void CMystatic::DrawItem(LPDRAWITEMSTRUCT pdi)
{

exitparm.pdi = pdi;
exitparm.sizeptr = &strsize;

(drawptr)(myexitparm);

}

Here is the C DLL

typedef struct EXITPARM
{
LPDRAWITEMSTRUCT pdi;
SIZE* sizeptr;

};
// void ownerdraw(exitparmptr);
typedef struct EXITPARM* exitparmptr;
__declspec(dllexport) void ownerdraw(exitparmptr parmptr);

void ownerdraw(exitparmptr parmptr)
{

LPDRAWITEMSTRUCT pdi = parmptr->pdi;

// (char*)myexit += 8;
SIZE* mysize = parmptr->sizeptr;

[Victor Nijegorodov]

I never saw such an error/warning in my code. What I see in your code snippet (and it is was I don't like) is this expression:

void ownerdraw(exitparmptr parmptr)
{
LPDRAWITEMSTRUCT pdi = parmptr->pdi;

What happens when the function argument parmptr is nullptr? Yes, the program crash!

[ForNow]

Right upon exiting the C DLL it crashed really don’t think there is any stack storage corruption when I turned if /GS option all was okay Just wondering going from inside a MFC C++ method to C DLL any special calling convention think__cedcl is the default