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SuppressUnmanagedCodeSecurityAttribute Class

Allows managed code to call into unmanaged code without a stack walk. This class cannot be inherited.

For a list of all members of this type, see SuppressUnmanagedCodeSecurityAttribute Members.


[Visual Basic]
<AttributeUsage(AttributeTargets.Class Or AttributeTargets.Method _
   Or AttributeTargets.Interface)>
NotInheritable Public Class SuppressUnmanagedCodeSecurityAttribute
   Inherits Attribute
[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method |
public sealed class SuppressUnmanagedCodeSecurityAttribute :
[AttributeUsage(AttributeTargets::Class | AttributeTargets::Method
   | AttributeTargets::Interface)]
public __gc __sealed class SuppressUnmanagedCodeSecurityAttribute
   : public Attribute
   AttributeUsage(AttributeTargets.Class | AttributeTargets.Method |
class SuppressUnmanagedCodeSecurityAttribute extends

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.


CAUTION   Use this attribute with extreme care. Incorrect use can create security weaknesses.

This attribute can be applied to methods that want to call into native code without incurring the performance loss of a run-time security check when doing so. The stack walk performed when calling unmanaged code is omitted at run time, resulting in substantial performance savings. Using this attribute in a class applies it to all contained methods.

Generally, whenever managed code calls into unmanaged code (by PInvoke or COM interop into native code), there is a demand for the UnmanagedCode permission to ensure all callers have the necessary permission to allow this. By applying this explicit attribute, developers can suppress the demand at run time. The developer must take responsibility for assuring that the transition into unmanaged code is sufficiently protected by other means. The demand for the UnmanagedCode permission will still occur at link time. For example, if function A calls function B and function B is marked with SuppressUnmanagedCodeSecurityAttribute, function A will be checked for unmanaged code permission during just-in-time compilation, but not subsequently during run time.

This attribute is only effective when applied to PInvoke methods (or classes containing PInvoke methods) or the definition of an interface through which interop calls will be made. It will be ignored in all other contexts.

This attribute is useful for implementing a class that provides access to system resources through unmanaged code. Code that does not have permission to access unmanaged code can call a class with this attribute to access unmanaged code. This is only safe if the writer of the class with this attribute has programmed the class to be secure. If not, this attribute is dangerous and can allow the code that uses it to be misused.

This is not a declarative security attribute, but a regular attribute (it derives from Attribute, not SecurityAttribute).


Namespace: System.Security

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

Assembly: Mscorlib (in Mscorlib.dll)

See Also

SuppressUnmanagedCodeSecurityAttribute Members | System.Security Namespace | Extending Metadata Using Attributes | Security Optimizations