Intel Extensible Firmware Interface - Manual (Page 195)

Services — Runtime Services
Version 1.10 12/01/02 6-3
GetVariable()
Summary
Returns the value of a variable.
Prototype
EFI_STATUS
GetVariable (
IN CHAR16 *VariableName,
IN EFI_GUID *VendorGuid,
OUT UINT32 *Attributes OPTIONAL,
IN OUT UINTN *DataSize,
OUT VOID *Data
);
Parameters
VariableName A Null-terminated Unicode string that is the name of the
vendor’s variable.
VendorGuid A unique identifier for the vendor. Type EFI_GUID is defined
in the InstallProtocolInterface() function
description.
Attributes If not NULL , a pointer to the memory location to return the
attributes bitmask for the variable. See “Related Definitions.”
DataSize On input, the size in bytes of the return Data buffer.
On output the size of data returned in Data .
Data The buffer to return the contents of the variable.
Related Definitions
//*******************************************************
// Variable Attributes
//*******************************************************
#define EFI_VARIABLE_NON_VOLATILE
0x0000000000000001
#define EFI_VARIABLE_BOOTSERVICE_ACCESS 0x0000000000000002
#define EFI_VARIABLE_RUNTIME_ACCESS 0x0000000000000004