c++ - 我仍然可以从 catch block 中调用的函数中重新抛出异常吗？

Question

我在遗留代码库中有以下结构:

try{
...
}
catch(Type1&){
...
}
catch(Type2&){
...
}
...

通过复制粘贴开发，相同的 catch block 随处可见。现在，我会写一个这样的函数:

void catchErrors(){
  try{
    throw;
  }
  catch(Type1&){
    ...
  }
  ...
}

然后像这样把它放到代码中:

try{
  ...
}
catch(...){
  catchErrors();
}

这会是一个有效的重构，从而产生相同的功能吗？
(您对重构有什么更好的建议吗？)

Answer 1

是的，这是有效的。

[C++14: 15.1/8]: A throw-expression with no operand rethrows the currently handled exception (15.3). The exception is reactivated with the existing exception object; no new exception object is created. The exception is no longer considered to be caught; therefore, the value of std::uncaught_exception() will again be true.

[ Example: code that must be executed because of an exception yet cannot completely handle the exception can be written like this:

try {
  // ...
} catch (...) { // catch all exceptions
  // respond (partially) to exception
  throw; // pass the exception to some
  // other handler
}

—end example ]

[C++14: 15.1/9]: If no exception is presently being handled, executing a throw-expression with no operand calls std::terminate() (15.5.1).

虽然 throw-expression 已经被移动到它自己的函数中，但在它执行期间仍然会处理异常，所以它仍然有效:

#include <iostream>

void bar()
{
    try {
        throw;
    }
    catch (int x) {
        std::cerr << "Damn " << x << "!\n";
    }
}

void foo()
{
    try {
        throw 42;
    }
    catch (...) {
        bar();
    }
}

int main()
{
    foo();
}

// Output: Damn 42!

( live demo )