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 }