Thread
Handling
See Also:� ucNewThread, ucExprThread, ucReleaseItem
uCalc Fast Math Parser allows you to group definitions and evaluations into independent threads.� Whatever you define or evaluate in one thread group is invisible to other thread groups.� To allocate a new thread group, use ucNewThread.� This will return a handle that you can pass as the last argument to functions such as ucParse, ucDefine, ucDefineFunction, ucDefineVariable, etc.
You can re-organize functions in the include file into a class.� The details will vary from compiler to compiler.� But generally, when the class is constructed, you should call ucNewThread to obtain a handle for the object instance.�� ucParse, ucDefine, etc., should each be defined as members of the class, and you should use the thread handle with each of these functions.� When the class instance is destroyed, you should call ucReleaseItem with the handle of the thread.
Current Thread
A native callback routine can retrieve the handle of the current thread that called it, using ucExprThread.
Releasing a thread
You can release a thread using ucReleaseItem with the handle of the thread.� This will de-allocate all definitions associated with the thread.� This can be compared to version 2.0's ucReset routine, except only the given thread is released.� When you release a thread, all of its sub-threads are also released.� Generally, it is best to avoid releasing the default thread, which is where the default functions and operators are defined.
Visual Basic
|
' Default (parent) thread definition ucDefine
"Const: Pi = Atan(1)*4" ' Thread A definitions tHandle_A
= ucNewThread() ucDefineFunction
"COSINE(x) = COS(x)", 0, tHandle_A ucDefineVariable
"IndyVar = 20", 0, tHandle_A ' Thread B definitions tHandle_B
= ucNewThread() ucDefineFunction
"COSINE(x) = COS(x * Pi / 180)", 0, tHandle_B ucDefineVariable
"IndyVar = 50", 0, tHandle_B ' Printout Print ucEval("Pi"),
ucEval("Pi", tHandle_A),
ucEval("Pi", tHandle_B) Print ucEval("IndyVar"), ucEval("IndyVar", tHandle_A), ucEval("IndyVar", tHandle_B) Print ucEval("COSINE(60)"),
ucEval("COSINE(60)", tHandle_A),
ucEval("COSINE(60)", tHandle_B) |
If you run the above example, you will get the following results:
Expression����� Default thread���� Thread
A���� Thread B
Pi������������� 3.14159...�������� 3.14159...�� 3.14159...
IndyVar�������� Undefined��������� 20���������� 50
COSINE(60)����� Undefined�������� -0.95241...�� 0.5
New or enhanced in version 3.0
� Nothing related to this topic.
� See What's New in version 3.0.
New or enhanced in version 2.96