Running asynchronous agents on the Domino® server

Thread-safe LSX, C/C++ code

Notes® is thread-safe. To write multithreaded agents, you must make sure your LSX or C/C++ code is thread-safe.

Thread-safe code means one of the following:

• The code shares no resources with other execution threads.
• The code shares resources with other execution threads but locks prevent concurrent access.

To design thread-safe code:

• Use only stack-allocated and dynamically-allocated memory in C or C++, such as, function/method local or calloc/malloc/new.
• Do not pass pointers between threads.
• If you must use static declarations, module level variables, or pass pointers, use locks.

Thread-specific bugs

Threading problems are usually non-deterministic.

Common threading problems include:

• Lost updates
• Partial updates
• Deadlock
• Thread calls non-thread-safe code

Creating and destroying locks

To create locks, use the command:

LockID=CreateLock( LockName as String)

This command creates a link to the specified lock and returns the lock ID used by other lock primitives. It creates a lock if one doesn't exist.

To remove locks, use the command

DestroyLock ( LockID as Integer)

This command removes the current link to the lock specified and destroys the lock if no links remain.