Applying a Qualifier

Like many other techniques in Managed Object Format (MOF), applying a qualifier to your code is a relatively simple process.

The only real challenges are the following restrictions in naming conventions that WMI enforces:

  • A qualifier can describe a class, instance, property, method, or method parameter.
  • Qualifier names cannot have either leading or trailing underscores.
  • A qualifier name cannot begin with a digit.
  • A qualifier name cannot contain special characters such as & * @ ! ~ \ /.
  • All qualifier names are case-insensitive.
  • You cannot redefine the standard WMI qualifiers or any qualifiers described in the DMTF CIM specification.
  • Qualifier types are not explicitly declared.

    If you do not declare a qualifier type, WMI assumes the type as Boolean with a value of TRUE. Otherwise, WMI types qualifiers based on the qualifier values you declare.

  • When creating your own qualifiers, you should prefix your schema name to your qualifier name.

    The purpose of this rule is to avoid confusion with new qualifiers.

  • You can create homogeneous arrays of qualifiers.

    The following code example shows how qualifier arrays are specified with curly braces that surround the values.

    [StringArray{"hello", "there"}, SingleElementArray{3}]
  • WMI does not support automation types not listed in the reference, such as VT_NULL. For more information, see MOF Data Types.

The following procedure helps you to use C++ to add a qualifier to a property.

Aa384787.wedge(en-us,VS.85).gifTo apply a qualifier using C++

The following procedure helps you to apply a qualifier in MOF files.

Aa384787.wedge(en-us,VS.85).gifTo describe a keyword or identifier with a qualifier using MOF

  • Place a qualifier in brackets before the keyword or identifier described by the qualifier.

    The following code example shows how qualifiers are used.

    class StdDisk
      [qualifiers...]  uint32 dwNumCylinders;
      [qualifiers...]  uint32 dwNumHeads;
      [qualifiers...]  sint32 Method1();
      sint32 Method2([qualifiers...] Parameter1);

    The following example describes the proper placement of qualifiers.

    class MyClass
        [Amendment, InstanceOf]  uint32 dwNumber;
        sint32 MyMethod ([in] sint32 Param);