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DebuggableAttribute.DebuggingModes Enumeration
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DebuggableAttribute.DebuggingModes Enumeration

Specifies the debugging mode for the just-in-time (JIT) compiler.

This enumeration has a FlagsAttribute attribute that allows a bitwise combination of its member values.

Namespace:  System.Diagnostics
Assembly:  mscorlib (in mscorlib.dll)

public enum DebuggingModes

Member nameDescription
Supported by the XNA FrameworkSupported by Portable Class LibraryDefaultInstructs the just-in-time (JIT) compiler to use its default behavior, which includes enabling optimizations, disabling Edit and Continue support, and using symbol store sequence points if present. Starting with the .NET Framework version 2.0, JIT tracking information, the Microsoft intermediate language (MSIL) offset to the native-code offset within a method, is always generated.
Supported by the XNA FrameworkSupported by Portable Class LibraryDisableOptimizationsDisable optimizations performed by the compiler to make your output file smaller, faster, and more efficient. Optimizations result in code rearrangement in the output file, which can make debugging difficult. Typically optimization should be disabled while debugging. In versions 2.0 or later, combine this value with Default (Default | DisableOptimizations) to enable JIT tracking and disable optimizations.
Supported by the XNA FrameworkSupported by Portable Class LibraryEnableEditAndContinueEnable edit and continue. Edit and continue enables you to make changes to your source code while your program is in break mode. The ability to edit and continue is compiler dependent.
Supported by the XNA FrameworkSupported by Portable Class LibraryIgnoreSymbolStoreSequencePointsUse the implicit MSIL sequence points, not the program database (PDB) sequence points. The symbolic information normally includes at least one Microsoft intermediate language (MSIL) offset for each source line. When the just-in-time (JIT) compiler is about to compile a method, it asks the profiling services for a list of MSIL offsets that should be preserved. These MSIL offsets are called sequence points.
Supported by the XNA FrameworkSupported by Portable Class LibraryNoneStarting with the .NET Framework version 2.0, JIT tracking information is always generated, and this flag has the same effect as Default, except that it sets the DebuggableAttribute.IsJITTrackingEnabled property to false. However, because JIT tracking is always enabled, the property value is ignored in version 2.0 or later. Note that, unlike the None flag, the None flag cannot be used to disable JIT optimizations.

The DebuggableAttribute.DebuggingModes enumeration specifies how the runtime is to track information important to the debugger during code generation. This information helps the debugger provide a rich debugging experience. Unlike the .NET Framework version 1.1, versions 2.0 or later do not allow you to turn off tracking by the just-in-time (JIT) compiler. JIT tracking is always enabled for debuggable files. In version 2.0 and later, the enumeration values have the following effect.

Debugging mode



Tracking on, JIT optimizations enabled


Tracking on, JIT optimizations enabled


Tracking on, JIT optimizations enabled

Default | DisableOptimizations

Tracking on, JIT optimizations disabled

Sequence points are used to indicate locations in the Microsoft intermediate language (MSIL) code that a debugger user will expect to be able to refer to uniquely, such as for setting a breakpoint. The JIT compiler ensures it does not compile the MSIL at two different sequence points into a single native instruction. By default, the JIT compiler examines the symbol store in the program database (PDB) file for a list of additional sequence points. However, loading the PDB file requires that the file be available and has a negative performance impact. Starting with version 2.0, compilers can emit "implicit sequence points" in the MSIL code stream through the use of MSIL "nop" instructions. Such compilers should set the IgnoreSymbolStoreSequencePoints flag to notify the common language runtime to not load the PDB file.


This enumeration is primarily used by language developers. It is generally not used in application development. Development environments use DebuggableAttribute.DebuggingModes based on compiler parameters such as /debug and /optimize.

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0, 2.0, 1.0

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

Portable Class Library

Supported in: Portable Class Library
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