Unmanaged Modules

The discussion of unmanaged methods in the previous section assumed that the methods resided in an otherwise managed module and assembly. The CLR also supports calling code in unmanaged modules to allow the use of legacy C DLLs and API functions. One exposes this capability via a technology called P/Invoke.

P/Invoke is a superset of the managed and unmanaged transitions just described. P/Invoke provides a rich set of type conversion facilities to deal with the inherent differences between legacy C DLLs and the CLR. In addition to implementing the execution mode switch just described, P/Invoke performs a security permission demand to ensure that the security of the system is not compromised. Like the ability to execute nonverifiable ...

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