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Initialize variable argument list

     #include <stdarg.h>
     void va_start(va_list AP, RIGHTMOST);
Use `va_start' to initialize the variable argument list AP, so that
`va_arg' can extract values from it.  RIGHTMOST is the name of the last
explicit argument in the parameter list (the argument immediately
preceding the ellipsis `...' that flags variable arguments in an ANSI C
function header).  You can only use `va_start' in a function declared
using this ellipsis notation (not, for example, in one of its
`va_start' does not return a result.
ANSI C requires `va_start'.