code: def descr_prototype(self, buf):
          
          state = "define" if self.blocks else "declare"
          ret = self.return_value
          args = ", ".join(str(a) for a in self.args)
          name = self.get_reference()
          attrs = self.attributes
          if any(self.args):
              vararg = ', ...' if self.ftype.var_arg else ''
          else:
              vararg = '...' if self.ftype.var_arg else ''
          linkage = self.linkage
          cconv = self.calling_convention
          prefix = " ".join(str(x) for x in [state, linkage, cconv, ret] if x)
          metadata = self._stringify_metadata()
          prototype = "{prefix} {name}({args}{vararg}) {attrs}{metadata}\n".format(
              prefix=prefix, name=name, args=args, vararg=vararg,
              attrs=attrs, metadata=metadata)
          buf.append(prototype)
docs: Describe the prototype ("head") of the function.