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VCCLCompilerTool.UndefinePreprocessorDefinitions Property 

Gets or sets a value that specifies one or more preprocessor undefines. UndefinePreprocessorDefinitions exposes the functionality of the C++ compiler's /U option and the MIDL compiler's /U option.

Namespace: Microsoft.VisualStudio.VCProjectEngine
Assembly: Microsoft.VisualStudio.VCProjectEngine (in microsoft.visualstudio.vcprojectengine.dll)

property String^ UndefinePreprocessorDefinitions {
	String^ get ();
	void set ([InAttribute] String^ Undefines);
/** @property */
String get_UndefinePreprocessorDefinitions ()

/** @property */
void set_UndefinePreprocessorDefinitions (/** @attribute InAttribute() */ String Undefines)

function get UndefinePreprocessorDefinitions () : String

function set UndefinePreprocessorDefinitions (Undefines : String)

Property Value

A string that specifies one or more preprocessor undefines.

See Examples for Project Model Extensibility for information about how to compile and run this example.

The following example modifies the compiler's UndefinePreprocessorDefinitions property in the integrated development environment (IDE):

' add reference to Microsoft.VisualStudio.VCProjectEngine.
Imports EnvDTE
Imports Microsoft.VisualStudio.VCProjectEngine

Public Module Module1
    Sub Test()
        Dim prj As VCProject
        Dim cfgs, tools As IVCCollection
        Dim cfg As VCConfiguration
        Dim tool As VCCLCompilerTool
        Dim oldUndefs As String
        prj = DTE.Solution.Projects.Item(1).Object
        cfgs = prj.Configurations
        cfg = cfgs.Item(1)
        tool = cfg.Tools("VCCLCompilerTool")
        oldUndefs = tool.UndefinePreprocessorDefinitions
        tool.UndefinePreprocessorDefinitions = "_DEBUG;" + oldUndefs
    End Sub
End Module