C++ Primer, Fifth Edition

6.2.6. Functions with Varying Parameters

Sometimes we do not know in advance how many arguments we need to pass to a function. For example, we might want to write a routine to print error messages generated from our program. We’d like to use a single function to print these error messages in order to handle them in a uniform way. However, different calls to our error-printing function might pass different arguments, corresponding to different kinds of error messages.

The new standard provides two primary ways to write a function that takes a varying number of arguments: If all the arguments have the same type, we can pass a library type named initializer_list. If the argument types vary, we can write a special kind of function, known as a variadic ...