cstdarg (stdarg.h)

This header defines macros to access the individual arguments of a list of unnamed arguments whose number and types are not known to the called function.

A function may accept a varying number of additional arguments without corresponding parameter declarations by including a comma and three dots (,...) after its regular named parameters:

return_type function_name ( parameter_declarations , ... );
To access these additional arguments the macros va_start, va_arg and va_end, declared in this header, can be used:

• First, va_start initializes the list of variable arguments as a va_list.
• Subsequent executions of va_arg yield the values of the additional arguments in the same order as passed to the function.
• Finally, va_end shall be executed before the function returns.

The header, describes one type:

va_list

Type to hold information about variable arguments (type )

And three functions:

va_start

Initialize a variable argument list (macro)

va_arg

Retrieve next argument (macro)

va_end

End using variable argument list (macro)

Some implementations of C compilers (such as ISO C99-compliant compilers) also include a va_copy macro to duplicate a va_list object, but this is not part of ISO C++ standard.