You can use the function parse_printf_format to obtain
information about the number and types of arguments that are
expected by a given template string. This function permits
interpreters that provide interfaces to printf to avoid passing
along invalid arguments from the user's program, which could
cause a crash. All the symbols described in this section are
declared in the header file printf.h. This function returns
information about the number and types of arguments expected by
the printftemplate string template. The information is stored in
the array argtypes; each element of this array describes one
argument. This information is encoded using the various ‘PA_’
macros, listed below. The argument n specifies the number of
elements in the array argtypes. This is the maximum number of
elements that parse_printf_formatwill try to write.
parse_printf_formatreturns the total number of arguments
required by template. If this number is greater than n, then the
information returned describes only the first n argume