A15-1-1 - Unofficial Autosar C++ Guidelines Reference

Rule A15-1-1 (advisory, implementation, automated)

Only instances of types derived from std::exception should be thrown.

Rationale

If an object that inherits from std::exception is thrown, there’s a guarantee that it serves to document the cause of an exception in an unified way. Also, "it makes your code easier to learn and re-use, because it matches established conventions with which programmers are already familiar.". [Effective Java 2nd Edition [15]] This means that only standard library exceptions or user-defined exceptions that inherit from std::exception base class should be used for exceptions. Note that direct instances of std::exception are not to be thrown as they can not be unique.

Example

//% $Id: A15-1-1.cpp 289436 2017-10-04 10:45:23Z michal.szczepankiewicz $
#include <memory>
#include <stdexcept>
class A

{
// Implementation
};
class MyException : public std::logic_error
{
public:
using std::logic_error::logic_error;
// Implementation
};
void F1()
{
throw - 1; // Non-compliant - integer literal thrown
}
void F2()
{
throw nullptr; // Non-compliant - null-pointer-constant thrown
}
void F3()
{
throw A();
Non-compliant - user-defined type that does not inherit from
std::exception thrown
}
void F4()
{
throw std::logic_error{
"Logic Error"}; // Compliant - std library exception thrown
}
void F5()
{
throw MyException{"Logic Error"}; // Compliant - user-defined type that
// inherits from std::exception thrown
}
void F6()
{
throw std::make_shared<std::exception>(
std::logic_error("Logic Error")); // Non-compliant - shared_ptr does
// not inherit from std::exception
}
void F7()
{
try
{
F6();
}

catch (std::exception& e) // An exception of
// std::shared_ptr<std::exception> type will not
// be caught here

{
// Handle an exception
}

catch (std::shared_ptr<std::exception>& e) // An exception of
// std::shared_ptr<std::exception>
// type will be caught here, but
// unable to access
// std::logic_error information
{
// Handle an exception
}
}

Unofficial Autosar C++ Guidelines Reference

Rationale

Example

See also