[译]C++异常的幕后4：捕捉你抛出的异常

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#include "throw.h"

#include <stdio.h>

// Notice we're adding a second exception type

struct Fake_Exception {};

void raise() {

    throw Exception();

}

// We will analyze what happens if a try block doesn't catch an exception

void try_but_dont_catch() {

    try {

        raise();

    } catch(Fake_Exception&) {

        printf("Running try_but_dont_catch::catch(Fake_Exception)\n");

    }

    printf("try_but_dont_catch handled an exception and resumed execution");

}

// And also what happens when it does

void catchit() {

    try {

        try_but_dont_catch();

    } catch(Exception&) {

        printf("Running try_but_dont_catch::catch(Exception)\n");

    } catch(Fake_Exception&) {

        printf("Running try_but_dont_catch::catch(Fake_Exception)\n");

    }

    printf("catchit handled an exception and resumed execution");

}

extern "C" {

    void seppuku() {

        catchit();

    }

}

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> g++ -c -o throw.o -O0 -ggdb throw.cpp

> gcc main.o throw.o mycppabi.o -O0 -ggdb -o app

throw.o: In function `try_but_dont_catch()':

throw.cpp:12: undefined reference to `__cxa_begin_catch'

throw.cpp:12: undefined reference to `__cxa_end_catch'

throw.o: In function `catchit()':

throw.cpp:20: undefined reference to `__cxa_begin_catch'

throw.cpp:20: undefined reference to `__cxa_end_catch'

throw.o:(.eh_frame+0x47): undefined reference to `__gxx_personality_v0'

collect2: ld returned 1 exit status