ACPI_EVAL_INPUT_BUFFER_SIMPLE_STRING_V1_EX structure

The ACPI_EVAL_INPUT_BUFFER_SIMPLE_STRING_EX structure is used as input to an IOCTL_ACPI_EVAL_METHOD_EX request and to an IOCTL_ACPI_ASYNC_EVAL_METHOD_EX request. The structure supplies the path and name of a control method in an ACPI namespace and an input argument that is an ASCII string.

Syntax

typedef struct _ACPI_EVAL_INPUT_BUFFER_SIMPLE_STRING_V1_EX {
  ULONG Signature;
  CHAR  MethodName[256];
  ULONG StringLength;
  UCHAR String[ANYSIZE_ARRAY];
} ACPI_EVAL_INPUT_BUFFER_SIMPLE_STRING_V1_EX, *PACPI_EVAL_INPUT_BUFFER_SIMPLE_STRING_V1_EX, ACPI_EVAL_INPUT_BUFFER_SIMPLE_STRING_EX, *PACPI_EVAL_INPUT_BUFFER_SIMPLE_STRING_EX;

Members

Signature

The signature of an extended string input buffer that must be set to ACPI_EVAL_INPUT_BUFFER_SIMPLE_STRING_SIGNATURE_EX.

MethodName

A NULL-terminated ASCII string that contains the path and name of a control method in an ACPI namespace. The maximum number of characters that the string can contain, including a NULL terminator, is 256. For more information about how to supply the path and name of a control method, see the Remarks section later in this topic.

StringLength

The number of ASCII characters in the array of characters that is supplied by String.

String

An ASCII character array that contains the number of characters that is specified by StringLength. The character array does not include a NULL terminator.

Remarks

A driver for a device can use an IOCTL_ACPI_EVAL_METHOD_EX request or an IOCTL_ACPI_ASYNC_EVAL_METHOD_EX request to evaluate a control method that is a descendant child object of the device. If the method takes a single string input argument, these requests take an input ACPI_EVAL_INPUT_BUFFER_STRING_EX structure as follows:

  • Set Signature to ACPI_EVAL_INPUT_BUFFER_SIMPLE_STRING_SIGNATURE_EX.
  • Set MethodName to a NULL-terminated string that supplies either the full path and name to a control method in the ACPI namespace or the path and name of the method that is relative to the device to which the evaluation request is sent.

    For example, assume that a request is sent to a device named 'ABCD,' which is an immediate child of the root of an ACPI namespace, that 'ABCD' device supports a child device named 'CHLD,' and that the 'CHLD' device supports a method named '_FOO.' In this case, the evaluation request can supply either '\ABCD.CHLD._FOO,' which is the fully qualified path and name of the control method in the ACPI namespace, or 'CHLD._FOO,' which is the path and name of the control method that is relative to the 'ABCD' device in the ACPI namespace.

    For more information about how to obtain the fully qualified path and name of a control method in an ACPI namespace, see Enumerating Child Devices and Control Methods.

  • Set StringLength to the number of characters in String.
  • Set String to the input string.
For more information about how to use this structure, see Evaluating ACPI Control Methods.

Requirements

   
Minimum supported client Windows Vista and later versions of Windows.
Header acpiioct.h (include Acpiioct.h)

See Also

IOCTL_ACPI_ASYNC_EVAL_METHOD_EX

IOCTL_ACPI_EVAL_METHOD_EX