CA2004: Remove calls to GC.KeepAlive

Applies to: Visual Studio Visual Studio for Mac

Note

This article applies to Visual Studio 2017. If you're looking for the latest Visual Studio documentation, see Visual Studio documentation. We recommend upgrading to the latest version of Visual Studio. Download it here

Item	Value
RuleId	CA2004
Category	Microsoft.Reliability
Breaking change	Non-breaking

Cause

Classes use SafeHandle but still contain calls to GC.KeepAlive.

Rule description

If you are converting to SafeHandle usage, remove all calls to GC.KeepAlive (object). In this case, classes should not have to call GC.KeepAlive,assuming they do not have a finalizer but rely on SafeHandle to complete the OS handle for them. Although the cost of leaving in a call to GC.KeepAlive might be negligible as measured by performance, the perception that a call to GC.KeepAlive is either necessary or sufficient to solve a lifetime issue that might no longer exist makes the code harder to maintain.

How to fix violations

Remove calls to GC.KeepAlive.

When to suppress warnings

You can suppress this warning only if it is not technically correct to convert to SafeHandle usage in your class.