CapeSoft MaxQueue

Global, Unthreaded Queues are bad because they are not thread safe. They were popular in Clarion 5.5 and earlier (because they could be safely used there) but from Clarion 6 they became unsafe, and should be removed, where possible from a program.  Unfortunately in large programs this is easier said than done, and replacing global unthreaded queues (with memory tables, or whatever) can be a large task.

MaxQueue offers an alternative to replacing global unthreaded queues, by making them thread safe. Changes are made at the global declaration level, but existing code which access the queue remains unaltered. [1] This increases the safety of the global queue, while at the same time reducing the number of changes required to existing code.

[1] Not all the queue functions are duplicated, so there are some possible places in the code where a compile error may occur. A simple alternate line of code can easily be used in these situations. The compiler will alert you to places where this is necessary.

While the supplied Queue procedures are adequate to read and write to the queue, there are cases where the syntax is clumsy. It is also notable that the syntax is similar to, but does not match the syntax for the file drivers. MaxQueue offers additional methods which can make processing queues simpler and more intuitive (and in some cases faster).

New methods include Set, Next, Previous, Copy, Merge, Add, Subtract and more.

Queues can be loaded from and to either StringTheory objects, or a text file, using Load, Save, LoadFile,SaveFile.

It is possible, and reasonably straight-forward to create Queues-in-Queues. However working with these can tricky, and if they are not free'd correctly then they can lead to memory leaks. By linking into the Reflection accessory (which is free) safe Queue disposes are done internally using the normal FREE method.