throw on catch

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见到cm中由于在catch中throw没catch引起的crash, 总结一下.
实验

// @file testcase05101520.cpp : Defines the entry point for the console application.// @brief test throw on catch// @note 对于描述为throw的c++的接口定义, 必须try-catch住.//      对于接口是否会抛出异常, 可以在接口描述中叙述, 也可以在接口定义中用throw描述//      e.g. void CMyExp::DoThrowA(); void CMyExp::DoThrowB() throw(exception)#include "stdafx.h"#include <stdlib.h>#include <stdio.h>#include <string>#include <exception>using namespace std;class CMyExp : public std::exception {public:    CMyExp() {m_str_what = "MyExp";}    virtual ~CMyExp() {}    void setWhat(const char* pszWhat) {m_str_what = ((NULL != pszWhat) ? pszWhat : "MyExp");}    const char* what () const throw () {        return m_str_what.c_str();    }    // @fn DoThrowA    // @brief 接口中会抛出异常的例子A    // @param NULL    // @note 会抛出 exception e异常    // @return void    void DoThrowA() {        exception e("DoThrowA");        throw e;    }    // @fn DoThrowB    // @brief 接口中会抛出异常的例子B    // @param NULL    // @return void    void DoThrowB() throw(exception) {        exception e("DoThrowA");        throw e;    }private:    std::string m_str_what;};void fnTryCatch1_doTask();void fnTryCatch2_tryAgain();int main(int argc, char* argv[]){    fnTryCatch1_doTask();    system("pause");    /** run result    e.what = throw on fnTryCatch1_doTask    e.what = throw on fnTryCatch2_tryAgain    try again ok    */    return 0;}void fnTryCatch1_doTask(){    CMyExp e;    try {        // do something, when error, throw        e.setWhat("throw on fnTryCatch1_doTask");        throw(e);    }    catch (exception& e) {        printf("e.what = %s\n", e.what());        // 可以在这里进行try-catch嵌套        // 也可以将try-catch写入另外的函数fnB, 整洁些, 然后在catch中调用那个函数fnB        // 总之, 一个try(throw)必须要有一个catch, 否则throw或运行时其他异常(e.g. div0)没人接住，传到系统程序就报错了.        // 这样, 在catch中throw也是可以正常运行的        fnTryCatch2_tryAgain();    }}void fnTryCatch2_tryAgain(){    CMyExp e;    try {        // do something, when error, throw        // e.g. mongo c++ interface, maybe throw when call it        // so when call a c++ interface declare indicate throw, we will try catch it        e.setWhat("throw on fnTryCatch2_tryAgain");        throw(e);    }    catch (exception& e) {        printf("e.what = %s\n", e.what());        printf("try again ok\n");    }}
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