C++ 运行时，显示异常信息
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C++ runtime, display exception message
提问by Anycorn
I am using gcc on linux to compile C++ code. There are some exceptions which should not be handled and should close program. However, I would like to be able to display exception string:
我在 linux 上使用 gcc 来编译 C++ 代码。有一些不应该被处理并且应该关闭程序的异常。但是，我希望能够显示异常字符串：
For example:
例如：
throw std::runtime_error(" message");does not display message, only type of error.
I would like to display messages as well.
Is there way to do it?
throw std::runtime_error(" message");不显示消息，只显示错误类型。我也想显示消息。有办法吗？
it is a library, I really do not want to put catch statements and let library user decide. However, right now library user is fortran, which does not allow to handle exceptions. in principle, I can put handlers in wrapper code, but rather not to if there is a way around
它是一个库，我真的不想放置 catch 语句并让库用户决定。但是，现在库用户是fortran，它不允许处理异常。原则上，我可以将处理程序放在包装器代码中，但如果有办法的话就不要这样做
回答by
Standard exceptions have a virtual what()method that gives you the message associated with the exception:
标准异常有一个虚what()方法，它为您提供与异常相关的消息：
int main() {
try {
// your stuff
}
catch( const std::exception & ex ) {
cerr << ex.what() << endl;
}
}
回答by EFraim
You could write in main:
你可以在 main 中写：
try{
}catch(const std::exception &e){
std::cerr << e.what() << std::endl;
throw;
}
回答by Kirill V. Lyadvinsky
You could use try/catchblock and throw;statement to let library user to handle the exception. throw;statement passes control to another handler for the same exception.
您可以使用try/catch块和throw;语句让库用户处理异常。throw;语句将控制权传递给相同异常的另一个处理程序。
回答by frankc
I recommend making an adapter for your library for fortran callers. Put your try/catch in the adapter. Essentially your library needs multiple entry points if you want it to be called from fortran (or C) but still allow exceptions to propigate to C++ callers. This way also has the advantage of giving C++ linkage to C++ callers. Only having a fortran interface will limit you substantially in that everything must be passed by reference, you need to account for hidden parameters for char * arguments etc.
我建议为您的库为 fortran 调用者制作一个适配器。将您的 try/catch 放入适配器中。如果您希望从 fortran（或 C）调用它，但仍然允许异常传播到 C++ 调用者，那么基本上您的库需要多个入口点。这种方式还具有为 C++ 调用者提供 C++ 链接的优点。只有一个 fortran 接口会大大限制你，因为一切都必须通过引用传递，你需要考虑 char * 参数等的隐藏参数。
