C++ catch enum value as exception

问题

I am trying to use an external C++ library which have defined its exceptions as:

enum MY_ERRORS {
    ERR_NONE = 0,
    ERR_T1,
    ERR_T2,
};

Then in the code exceptions are thrown like this:

if(...) {
    throw ERR_T1;

Being new to programming in C++, I would do something like:

try {
    call_to_external_library();
} catch(??? err) {
    printf("An error occurred: %s\n", err);
} catch(...) {
    printf("An unexpected exception occurred.\n");
}

How do I determine what was thrown?

回答1:

You will need to write your code to handle the type of enumeration in the catch block:

try {
    call_to_external_library();
} catch(MY_ERRORS err) {      // <------------------------ HERE
    printf("An error occurred: %s\n", err);
} catch(...) {
    printf("An unexpected exception occurred.\n");
}

回答2:

You must catch the type MY_ERRORS and then compare against the possible values

try {
    call_to_external_library();
} catch(MY_ERRORS err) {
    printf("An error occurred: %s\n", err);
} catch(...) {
    printf("An unexpected exception occurred.\n");
}

来源：https://stackoverflow.com/questions/20951134/c-catch-enum-value-as-exception