Variable Operation

Description

Unicode string in Python is codded as u"string".

EfiPy provides GUID declare, which is similar to EDKII GUID declaration.

NULL (in C language) is codded as None in Python (also in ctypes/EfiPy).
Address of object in python ctypes, it is noted as byref() function

C compatible string in Python ctypes is used by create_string_buffer.

Sample code - simplest EDK II get variable by EfiPy

import EfiPy

VariableName  = u"EfiPyDemo"
VariableGuid  = EfiPy.EFI_GUID( 0x8BE4DF61, 0x93CA, 0x11d2, \
                  (0xAA, 0x0D, 0x00, 0xE0, 0x98, 0x03, 0x2B, 0x8D))
DataSize      = EfiPy.UINTN (0x00)

DataBuffer    = (EfiPy.CHAR8 * 5) ()

Attributes    = EfiPy.UINT32 ()

Status = EfiPy.gRT.GetVariable(

                     VariableName,

                     EfiPy.byref (VariableGuid),

                     EfiPy.byref (Attributes),

                     EfiPy.byref (DataSize),

                     EfiPy.byref (DataBuffer)

                     )

Screenshot

Sample code is at Sourceforge sample folder.