VCCLCompilerTool::UndefinePreprocessorDefinitions Property

Visual Studio 2015
 

Gets or sets a value that specifies one or more preprocessor undefines. UndefinePreprocessorDefinitions exposes the functionality of the C++ compiler's /U, /u (Undefine Symbols) option and the MIDL compiler's MIDL Property Pages: Advanced option.

Namespace:   Microsoft.VisualStudio.VCProjectEngine
Assembly:  Microsoft.VisualStudio.VCProjectEngine (in Microsoft.VisualStudio.VCProjectEngine.dll)

C#
C++
F#
VB
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property String^ UndefinePreprocessorDefinitions {
	String^ get();
	void set(String^ value);
}

Property Value

Type: System::String^

A string that specifies one or more preprocessor undefines.

See How to: Compile Example Code 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):

VB
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' 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
        MsgBox(tool.UndefinePreprocessorDefinitions)
    End Sub
End Module
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