A.2.2 How Variadic Functions are Defined and Used

Defining and using a variadic function involves three steps:

• Define the function as variadic, using an ellipsis (‘…’) in the argument list, and using special macros to access the variable arguments. See Receiving Arguments.
• Declare the function as variadic, using a prototype with an ellipsis (‘…’), in all the files which call it. See Variadic Prototypes.
• Call the function by writing the fixed arguments followed by the additional variable arguments. See Calling Variadics.