Cer Enumeration (System.Runtime.ConstrainedExecution)

Cer Enumeration

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Microsoft Visual Studio 2008/.NET Framework 3.5

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.NET Framework Class Library

Cer Enumeration

Specifies a method's behavior when called within a constrained execution region.

Namespace: System.Runtime.ConstrainedExecution
Assembly: mscorlib (in mscorlib.dll)

Syntax

Visual Basic (Declaration)

<SerializableAttribute> _
Public Enumeration Cer

Visual Basic (Usage)

Dim instance As Cer

[SerializableAttribute]
public enum Cer

Visual C++

[SerializableAttribute]
public enum class Cer

JScript

public enum Cer

Members

	Member name	Description
	None	The method, type, or assembly has no concept of a CER. It does not take advantage of CER guarantees. This implies the following: In the face of exceptional conditions the method might fail. The method might or might not report that it failed (it is non-deterministic). The method is not written with CERs in mind (which is the most likely scenario). If a method, type, or assembly is not explicitly marked to succeed, it is implicitly marked as Cer.None.
	MayFail	In the face of exceptional conditions, the method might fail. In this case, the method will report back to the calling method whether it succeeded or failed. The method must have a CER around the method body to ensure that it can report the return value.
	Success	In the face of exceptional conditions, the method is guaranteed to succeed. You should always construct a CER around the method that is called, even when it is called from within a non-CER region. A method is successful if it accomplishes what is intended. For example, marking Count with ReliabilityContractAttribute(Cer.Success) implies that when it is run under a CER, it always returns a count of the number of elements in the ArrayList and it can never leave the internal fields in an undetermined state.

Member name

Description

None

The method, type, or assembly has no concept of a CER. It does not take advantage of CER guarantees. This implies the following:

In the face of exceptional conditions the method might fail.
The method might or might not report that it failed (it is non-deterministic).
The method is not written with CERs in mind (which is the most likely scenario).

If a method, type, or assembly is not explicitly marked to succeed, it is implicitly marked as Cer.None.

MayFail

In the face of exceptional conditions, the method might fail. In this case, the method will report back to the calling method whether it succeeded or failed. The method must have a CER around the method body to ensure that it can report the return value.

Success

In the face of exceptional conditions, the method is guaranteed to succeed. You should always construct a CER around the method that is called, even when it is called from within a non-CER region. A method is successful if it accomplishes what is intended. For example, marking Count with ReliabilityContractAttribute(Cer.Success) implies that when it is run under a CER, it always returns a count of the number of elements in the ArrayList and it can never leave the internal fields in an undetermined state.

Remarks

The Cer enumeration specifies the behavior of a method, type, or assembly within a constrained execution region (CER). Use one of the three available values to indicate that the entity will succeed, has no knowledge of a CER, or might (deterministically) be able to report success or failure.

A CER provides guarantees that the region of code will execute uninterrupted even if an asynchronous exception such as an aborted thread out-of-memory exception, or stack overflow is raised.

Examples

The following code example demonstrates the use of the Cer enumeration when specifying a constrained execution region for a method. This code example is part of a larger example provided for the ReliabilityContractAttribute constructor.

[ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
[MethodImpl(MethodImplOptions.NoInlining)]
void StackDepth2()
{
    try
    {
        consistentLevel2 = false;
        if (depth == 2)
            Thread.Sleep(-1);
        StackDepth3();
    }
    finally
    {
        consistentLevel2 = true;
    }
}

Platforms

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Version Information

.NET Framework

Supported in: 3.5, 3.0, 2.0

Reference

System.Runtime.ConstrainedExecution Namespace

PrepareConstrainedRegions

PrepareMethod

Other Resources

Constrained Execution Regions

Reliability Best Practices