Boost C++ Application Development Cookbook - Second Edition

Returning a value or flag where there is no value

Imagine that we have a function that does not throw an exception and returns a value or indicates that an error has occurred. In Java or C# programming languages, such cases are handled by comparing a return value from a function value with a null pointer. If the function returned null, then an error has occurred. In C++, returning a pointer from a function confuses library users and usually requires slow dynamic memory allocation.