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title: "Debug Class (C++/CLI) | Microsoft Docs"
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---
# Debug Class (C++/CLI)
When using <xref:System.Diagnostics.Debug> in a Visual C++ application, the behavior does not change between a debug and a release build.  
  
## Remarks  
 The behavior for <xref:System.Diagnostics.Trace> is identical to the behavior for the Debug class, but is dependent on the symbol TRACE being defined. This means that you must `#ifdef` any Trace-related code to prevent debug behavior in a release build.  
  
## Example  
  
### Description  
 The following sample always executes the output statements, regardless of whether you compile with **/DDEBUG** or **/DTRACE**.  
  
### Code  
  
```  
// mcpp_debug_class.cpp  
// compile with: /clr  
#using <system.dll>  
using namespace System::Diagnostics;  
using namespace System;  
  
int main() {  
   Trace::Listeners->Add( gcnew TextWriterTraceListener( Console::Out ) );  
   Trace::AutoFlush = true;  
   Trace::Indent();  
   Trace::WriteLine( "Entering Main" );  
   Console::WriteLine( "Hello World." );  
   Trace::WriteLine( "Exiting Main" );  
   Trace::Unindent();  
  
   Debug::WriteLine("test");  
}  
```  
  
### Output  
  
```  
    Entering Main  
Hello World.  
    Exiting Main  
test  
```  
  
## Example  
  
### Description  
 To get the expected behavior (that is, no "test" output printed for a release build), you must use the `#ifdef` and `#endif` directives. The previous code sample is modified below to demonstrate this fix:  
  
### Code  
  
```  
// mcpp_debug_class2.cpp  
// compile with: /clr  
#using <system.dll>  
using namespace System::Diagnostics;  
using namespace System;  
  
int main() {  
   Trace::Listeners->Add( gcnew TextWriterTraceListener( Console::Out ) );  
   Trace::AutoFlush = true;  
   Trace::Indent();  
  
#ifdef TRACE   // checks for a debug build  
   Trace::WriteLine( "Entering Main" );  
   Console::WriteLine( "Hello World." );  
   Trace::WriteLine( "Exiting Main" );  
#endif  
   Trace::Unindent();  
  
#ifdef DEBUG   // checks for a debug build  
   Debug::WriteLine("test");  
#endif   //ends the conditional block  
}  
```  
  
## See Also  
 [.NET Programming with C++/CLI (Visual C++)](../dotnet/dotnet-programming-with-cpp-cli-visual-cpp.md)