class_docstr: The main top-level class that you instantiate once, or once per module.
  
  Example usage:
  
      ffi = FFI()
      ffi.cdef("""
          int printf(const char *, ...);
      """)
  
      C = ffi.dlopen(None)   # standard library
      -or-
      C = ffi.verify()  # use a C compiler: verify the decl above is right
  
      C.printf("hello, %s!\n", ffi.new("char[]", "world"))
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docstr: Return a callback object or a decorator making such a
  callback object.  'cdecl' must name a C function pointer type.
  The callback invokes the specified 'python_callable' (which may
  be provided either directly or via a decorator).  Important: the
  callback object must be manually kept alive for as long as the
  callback may be invoked from the C level.
code: def callback(
      self, cdecl, python_callable=None, error=None, onerror=None
  ):
      """Return a callback object or a decorator making such a
      callback object.  'cdecl' must name a C function pointer type.
      The callback invokes the specified 'python_callable' (which may
      be provided either directly or via a decorator).  Important: the
      callback object must be manually kept alive for as long as the
      callback may be invoked from the C level.
      """
  
      def callback_decorator_wrap(python_callable):
          if not callable(python_callable):
              raise TypeError(
                  "the 'python_callable' argument " "is not callable"
              )
          return self._backend.callback(
              cdecl, python_callable, error, onerror
          )
  
      if isinstance(cdecl, basestring):
          cdecl = self._typeof(cdecl, consider_function_as_funcptr=True)
      if python_callable is None:
          return callback_decorator_wrap  # decorator mode
      else:
          return callback_decorator_wrap(python_callable)
  
imports: import sys, types
  from .lock import allocate_lock
  from .error import CDefError
  from .None import model
label_desc: Use image node_id 20 for calling the FFI obj's underlying member method code with example usage: obj.callback(cdecl, python_callable, error, onerror) and returns: self, callback_decorator_wrap, callback_decorator_wrap