1、看看Qt源码中如何定义QT_TRY和QT_CATCH的：
1 inline void qt_noop(void) {} 2
3 /* These wrap try/catch so we can switch off exceptions later. 4 Beware - do not use more than one QT_CATCH per QT_TRY, and do not use 5 the exception instance in the catch block. 6 If you can't live with those constraints, don't use these macros. 7 Use the QT_NO_EXCEPTIONS macro to protect your code instead. 8 */
9
10 #ifdef QT_BOOTSTRAPPED 11 # define QT_NO_EXCEPTIONS 12 #endif
13 #if !defined(QT_NO_EXCEPTIONS) && defined(Q_CC_GNU) && !defined (__EXCEPTIONS) && !defined(Q_MOC_RUN)
14 # define QT_NO_EXCEPTIONS 15 #endif
16
17 #ifdef QT_NO_EXCEPTIONS 18 # define QT_TRY if (true) 19 # define QT_CATCH(A) else
20 # define QT_THROW(A) qt_noop() 21 # define QT_RETHROW qt_noop() 22 #else
23 # define QT_TRY try
24 # define QT_CATCH(A) catch (A) 25 # define QT_THROW(A) throw A 26 # define QT_RETHROW throw
27 #endif
2、我们来使用下QT的异常处理
1 // 在.pro 中增加如下配置 ==》 Qt默认是不开启异常的
2 CONFIG += exception
1 // main.cpp
2
3 enum Except{ EXCEP_ZERO,EXCEP_ONE}; 4
5 void func(int a){ 6 if(a ==0) throw (EXCEP_ZERO); // 抛出异常
7 } 8
9 int main(int argc, char *argv[]) 10 { 11 QApplication a(argc, argv); 12
13 QT_TRY { 14 func(1); 15 } QT_CATCH(Except ex) { 16 if(ex == EXCEP_ZERO) QT_RETHROW; 17 } 18
19
20
21 Widget w; 22 w.show(); 23 return a.exec(); 24 }