[RK_2014_1020]Cannot declare member function ‘static int Foo::bar()’ to have static linkage，declarefunction

[RK_2014_1020]Cannot declare member function ‘static int Foo::bar()’ to have static linkage，declarefunction

1.

if you declare a method to be static in your .cc file.

The reason is that static means something different inside .cc files than in class declarations It is really stupid, but the keyword static has three different meanings. In the .cc file, the static keyword means that the function isn't visible to any code outside of that particular file.

This means that you shouldn't use static in a .cc file to define one-per-class methods and variables. Fortunately, you don't need it. In C++, you are not allowed to have static variables or static methods with the same name(s) as instance variables or instance methods. Therefore if you declare a variable or method as static in the class declaration, you don't need the static keyword in the definition. The compiler still knows that the variable/method is part of the class and not the instance.

WRONG

 Foo.h:
 class Foo 
 {
   public: 
     static int bar();
 };
 Foo.cc:
 static int Foo::bar() 
 {
   // stuff
 }

WORKS

 Foo.h:
 class Foo 
 {
   public: 
     static int bar();
 };
 Foo.cc:
 int Foo::bar() 
 {
   // stuff
 }

A way to bypass this problem is to embed the defintion in the .h file, but this causes the function to be inline by default.

ALSO WORKS

 Foo.h:
 class Foo 
 {
   public: 
     static int bar()
       {
         // stuff
       };
 };

2.

test.cpp:285: cannot declare member function `static int
   CTest::testEtrance(short unsigned int)' to have static linkage

錯誤的原因就是在實現的地方不需要static了, 只在聲明的地方需要static

static int CTest::testEtrance(WORD  wCaseNO)

{

}

static 是多余的, 把static刪除就可以解決這樣的編譯錯誤.

3.本文網址[tom-and-jerry發布於2014-10-20 18:02]

http://www.cnblogs.com/tom-and-jerry/p/4037965.html 

function D=height(C) C=double(C) %將二值圖像C的類型轉化為double型 [Height,Width] = size(C); %計算圖

#include <windows.h>

/* Declare Windows procedure */
LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);

LRESULT CALLBACK ScrollProc(HWND, UINT, WPARAM, LPARAM);

int idFocus;
WNDPROC OldScroll[3];

/* Make the class name into a global variable */
char szClassName[ ] = "WindowsApp";

int WINAPI WinMain (HINSTANCE hThisInstance,
HINSTANCE hPrevInstance,
LPSTR lpszArgument,
int nFunsterStil)

{
HWND hwnd; /* This is the handle for our window */
MSG messages; /* Here messages to the application are saved */
WNDCLASSEX wincl; /* Data structure for the windowclass */

/* The Window structure */
wincl.hInstance = hThisInstance;
wincl.lpszClassName = szClassName;
wincl.lpfnWndProc = WindowProcedure; /* This function is called by windows */
wincl.style = CS_DBLCLKS; /* Catch double-clicks */
wincl.cbSize = sizeof (WNDCLASSEX);

/* Use default icon and mouse-pointer */
wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
wincl.lpszMenuName = NULL; /* No menu */
wincl.cbClsExtra = 0; /* No extra bytes after the window class */
wincl.cbWndExtra = 0; ......余下全文>>
 

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