C++ Coding Standards: 101 Rules, Guidelines, and Best Practices

73. Throw by value, catch by reference

Summary

Learn to catch properly: Throw exceptions by value (not pointer) and catch them by reference (usually to const). This is the combination that meshes best with exception semantics. When rethrowing the same exception, prefer just throw; to throw e;.

Discussion

When throwing an exception, throw an object by value. Avoid throwing a pointer, because if you throw a pointer, you need to deal with memory management issues: You can’t throw a pointer to a stack-allocated value because the stack will be unwound before the pointer reaches the call site. You could throw a pointer to dynamically allocated memory (if the error you’re reporting isn’t “out of memory” to begin with), but you’ve put the burden on ...