小编Nul*_*ptr的帖子

// API mathAPI.h,在Dll.cpp和Test.cpp中

#ifdef __APIBUILD
#define __API __declspec(dllexport)
//#error __APIBUILD cannot be defined.
#else
#define __API __declspec(dllimport)
#endif

class math
{
 public:
   static __API double Pi;
   static __API double Sum(double x, double y);
};

//定义了Dll.cpp __APIBUILD

#include "mathAPI.h"

double math::Pi = 3.14;

double math::Sum(double x, double y)
{
  return x + y;
}

// Test.cpp __APIBUILD未定义

#include <iostream>
#pragma comment(lib, "dll.lib")
#include "mathAPI.h"

int main()
{
  std::cout << math::Pi; //linker error
  std::cout << math::Sum(5.5, 5.5); //works fine
  return 0;
} …

我有一个像这样的函数来获取进程'id的名字,但它总是返回0我尝试的每个进程:

DWORD GetProcessId(std::string ProcessName)
{
HANDLE hsnap;
PROCESSENTRY32 pt;
DWORD PiD;
hsnap = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
pt.dwSize = sizeof(PROCESSENTRY32);
do {
    if (!strcmp(pt.szExeFile, ProcessName.c_str())) {
        CloseHandle(hsnap);
        PiD = pt.th32ProcessID;
        return PiD;
        if (PiD != NULL) {
            return 0;
        }
    }
} while (Process32Next(hsnap, &pt));
return 1;
}

主要功能:

int main()
{
DWORD pid = GetProcessId("calc.exe");
std::cout << pid;
if (pid == 0) { printf("error 1"); getchar(); }//error
return 0;
}

这是主要的"示例dlg.cpp"文件:

void CHelixV3Dlg::OnBnClickedCancel()
{
   CEdit* editbox = (CEdit*)GetDlgItem(IDC_EDIT1); 
  //works fine, defined as: *CWnd GetDlgItem(int nID); in this file
}

这是test.cpp源文件

void test()
{
   CEdit* editbox = (CEdit*)GetDlgItem(IDC_EDIT1);
   //does not work at all, seems to be a winAPI function instead of MFC...
   //defined as: HWND __stdcall GetDlgItem(HWND hDlg, int nIDDlgItem);
}

两个源文件都在同一个项目中,使用相同的头文件,但是test()的GetDlgItem显然是一个Win32 API函数,它在MFC中不起作用...我怎样才能在test.cpp中运行GetDlgItem()文件？

我试图调用函数testaddresscall(),其定义如下:

void testaddresscall()
{
   printf("success");
}

int main(void)
{
   void(*testaddresscallfunc)(void);
   testaddresscallfunc= &testaddresscall;
   cout << *testaddresscallfunc; //it printed 0x012D2050

   typedef void testfunc(void);
   testfunc* callbyaddress = (testfunc*)0x012D2050;
   callbyaddress();
}

然后发生这种情况

test.exe中0x012D2050处的未处理异常:0xC0000005:访问冲突执行位置0x012D2050.