AcxObjectBagRetrieveUI4 function (acxmisc.h)

Artikel
10/03/2023

The AcxObjectBagRetrieveUI4 function retrieves an unsigned int four byte UI4 (ULONG) value from an existing, initialized AcxObjectBag that contains values.

Syntax

NTSTATUS AcxObjectBagRetrieveUI4(
  ACXOBJECTBAG     ObjectBag,
  PCUNICODE_STRING ValueName,
  ULONG            *Value
);

Parameters

ObjectBag

An initialized ObjectBag ACX object. For more information, see ACX - Summary of ACX Objects.

ValueName

The name of the value that will be used to access the value.

Value

The Value to be retrieved from the ObjectBag.

Return value

Returns STATUS_SUCCESS if the call was successful. Otherwise, it returns an appropriate error code. For more information, see Using NTSTATUS Values.

Remarks

Example

This example shows the use of AcxObjectBagRetrieveUI4.

    ACXOBJECTBAG objBag     = NULL;
    ULONG        ui4Value   = 0;

    //Initialize an object bag configuration
    ACX_OBJECTBAG_CONFIG objBagCfg;
    ACX_OBJECTBAG_CONFIG_INIT(&objBagCfg);
    
    // Set the WDF attributes, and create an object bag 
    WDF_OBJECT_ATTRIBUTES_INIT(&attributes);
    attributes.ParentObject = Circuit;
    RETURN_NTSTATUS_IF_FAILED(AcxObjectBagCreate(&attributes, &objBagCfg, &objBag));

    // Enable deletion of the object bag when the function completes and goes out of scope
    auto objBag_scope = scope_exit([&objBag]() {
        if (objBag != NULL)
        {
            WdfObjectDelete(objBag);
        }
    });

    //Create Properties and add them to an object bag
    DECLARE_CONST_ACXOBJECTBAG_DRIVER_PROPERTY_NAME(VendorX, TestUI4);

    ui4Value = 1;
    RETURN_NTSTATUS_IF_FAILED(AcxObjectBagAddUI4(objBag, &TestUI4, ui4Value));

    // Retrieve the value from the object bag
    ui4Value = 0;
    RETURN_NTSTATUS_IF_FAILED(AcxObjectBagRetrieveUI4(objBag, &TestUI4, &ui4Value));

ACX requirements

Minimum ACX version: 1.0

For more information about ACX versions, see ACX version overview.

Requirements

Requirement	Value
Header	acxmisc.h
IRQL	PASSIVE_LEVEL

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