如何使用宏來替換賦值操作使用鎖定功能

Question

在一個函數的開始，我把這個宏來防止再次進入功能：

//For locking ISRs to prevent re-entrant execution when nested interrupts are enabled 
//-ex: to prevent re-entrant execution of this ISR even though ***nested interrupts are enabled!*** 
//-"return" is to exit the function if the ISR is locked 
#define functionLock()    \ 
    static bool ISR_locked = false; \ 
    if (ISR_locked==true)    \ 
    return;       \ 
    ISR_locked = true;    \ 

這工作。

當時我想用這個宏函數的結束重新啓用下一個入口函數進去：

#define functionUnlock() ISR_locked = false; 

但是，這無法編譯。錯誤：

error: '#' is not followed by a macro parameter 
error: 'functionLock' was not declared in this scope 
error: 'ISR_locked' was not declared in this scope 

我的第二個宏有什麼問題？

如果我只是刪除第二個宏並使用「ISR_locked = false;」直接在函數的末尾，它一切正常，但我想有一個匹配的宏來結束函數，而不是使用該行。

我們的目標是在函數中使用這些宏，就像這樣：

void myISR() 
{ 
    functionLock(); //locks the function to prevent re-entrant execution 
    //do stuff 
    functionUnlock(); 
} 

---

全小例子

#include <iostream> 
using namespace std; 

//macros: 
//For locking ISRs to prevent re-entrant execution when nested interrupts are enabled 
//-ex: to prevent re-entrant execution of this ISR even though ***nested interrupts are enabled!*** 
//-"return" is to exit the function if the ISR is locked 
#define functionLock()    \ 
    static bool ISR_locked = false; \ 
    if (ISR_locked==true)    \ 
    return;       \ 
    ISR_locked = true;    \ 
#define functionUnlock() ISR_locked = false; 

void myISR() 
{ 
    functionLock(); 
    cout << "hello"; 
    functionUnlock(); 
// ISR_locked = false; 
} 

int main() 
{ 
    myISR(); 
    return 0; 
} 

Answer 1

從functionLock定義的最後一行刪除\。