Setvariable() - Intel Extensible Firmware Interface Specification

Extensible Firmware Interface Specification
3.5.3

SetVariable()

Summary
Sets the value of a variable.
Prototype
EFI_STATUS
SetVariable (
IN CHAR16
IN EFI_GUID
IN UINT32
IN UINTN
IN VOID
);
Parameters
VariableName
VendorGuid
Attributes
DataSize
Data
Description
Variables are stored by the firmware and may maintain their values across power cycles. Each
vendor may create and manage its own variables without the risk of name conflicts by using a
unique VendorGuid.
Each variable has
Attributes
If the
EFI_VARIABLE_NON_VOLATILE
normal memory and it is not maintained across a power cycle. Such variables are used to pass
information from one component to another. An example of this is the firmware's language code
support variable. It is created at firmware initialization time for access by EFI components that
may need the information, but does not need to be backed up to non-volatile storage.
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*VariableName,
*VendorGuid,
Attributes,
DataSize,
*Data
A Null-terminated Unicode string that is the name of the
vendor's variable. Each
VendorGuid.
A unique identifier for the vendor. Type
in Section 3.3.1.
Attributes bitmask to set for the variable. See Section 3.5.1.
The size in bytes of the
Data
variable to be deleted.
The contents for the variable.
that define how the firmware stores and maintains the data value.
attribute is not set, the firmware stores the variable in
12/12/00
is unique for each
VariableName
EFI_GUID
buffer. A size of zero causes the
Version 1.02
is defined