如果我们在代码中重复定义一个宏(macro redefine)，例如：
#define SUM(a,b) a+b
#define SUM(a,b) a*b
会遇到下面的错误提示：
MRedef.c(20): error C2220: warning treated as error - no 'object' file generated
MRedef.c(20): warning C4005: 'SUM': macro redefinition
MRedef.c(19): note: see previous definition of 'SUM'
解决方法是在文件头部加入 Disable 这个 Warning 的指令如下：
#pragma warning (disable : 4005)
完整的代码如下：
#include <Uefi.h>
#include <Library/UefiLib.h>
#include <Library/ShellCEntryLib.h>
#pragma warning (disable : 4005)
/*
MRedef.c(20): error C2220: warning treated as error - no 'object' file generated
MRedef.c(20): warning C4005: 'SUM': macro redefinition
MRedef.c(19): note: see previous definition of 'SUM'
*/
#define SUM(a,b) a+b
#define SUM(a,b) a*b
/***
Print a welcoming message.
Establishes the main structure of the application.
@retval 0 The application exited normally.
@retval Other An error occurred.
***/
INTN
EFIAPI
ShellAppMain (
IN UINTN Argc,
IN CHAR16 **Argv
)
{
int c =3,d=4;
Print(L"Hello there fellow Programmer.\n");
Print(L"Welcome to the world of EDK II.\n");
Print(L"Macro test %d\n",SUM(c,d));
return(0);
}
参考：
1.https://stackoverflow.com/questions/25201724/fix-macro-redefinition-in-c