A small number of attributes affect the language in some way. These attributes include:

• System.AttributeUsageAttribute (24.4.1), which is used to describe the ways in which an attribute class can be used.
• System.ConditionalAttribute (24.4.2), which is used to define conditional methods.
• System.ObsoleteAttribute (24.4.3), which is used to mark a member as obsolete.

In This Section:

• 24.4.1: The AttributeUsage attribute
• 24.4.2: The Conditional attribute
• 24.4.3: The Obsolete attribute