| Command group | Flag affected | Reversible | Execute on client | Platform(s) |
|---|---|---|---|---|
| Threads | NO | NO | NO | All |
Begin critical block
Begin critical block is only applicable to the multithreaded server. It marks the start of a critical block, namely a section of code which needs to execute in single threaded mode without allowing other client methods to execute. You use End critical block to mark the end of a critical block.
One example of when you should use a critical block is as follows. Class variables are shared by all clients. Simple atomic operations, such as the direct assignment of a value to a class variable are safe. Other operations, such as when a method call is involved, could cause problems, because the method call might be interrupted by another thread. To avoid this, use a critical block.
Begin critical block
Calculate cClassVar as $cinst.$getvalue()
End critical block