en:software:qview:qview_6:qcl_library:sy10initializecriticalsection

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en:software:qview:qview_6:qcl_library:sy10initializecriticalsection [2017/04/04 17:05] – created qem103en:software:qview:qview_6:qcl_library:sy10initializecriticalsection [2019/08/29 17:01] (current) – external edit 127.0.0.1
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 +====== SY10InitializeCriticalSection ======
 +
 +**SY = **//System function//
 +
 +The SY10InitializeCriticalSection function __Initializes a critical section pooling information__.
 +
 +===== IMPLEMENTATION =====
 +
 +**SY10InitializeCriticalSection(pool)**
 +
 +Parameters:
 +
 +^IN/OUT^VARIABLE TYPE^EXAMPLE NAME^DIM^^
 +|  IN  |  ARRGBL  |  pool  |  B  |Critical section pools information|
 +
 +Description:
 +
 +Every critical section bases its inner workings on a proprietary data structure called //pool// informations.\\
 +Every critical section will have its own //pool// that must be initialized before it can be used.\\
 +The //pool// consists of an array of bytes where the number of items depends on the number of task unit that will use more two-byte fixed header.
 +
 +
 +Inglese
 +Italiano
 +If for example a given critical section is used in only two drives task you create an application pool of 4 byte making sure that a unit must use the ID 1 while the second the ID 2.
 +
 +The ID are progressive starting from 1 and identify the location of the information in the pool, then pass an ID with index not available in the pool means invalidating the call and how it works.
 +
 +**NB**: To avoid problems it is advisable to size the pool information with sufficient size to address all drives task.
 +
 +=== Example ===
 +
 +In the following example initializes an information pool used then to a critical section.
 +
 +
 +\\
 +**configuration unit:**
 +<code QCL>
 +; critical section consts
 +CONST
 + CS_POOL_HEADER 2 ; fixed header in critical section pool info
 + CS_POOL_SIZE 10 ; critical section pool info size
 +
 +ARRGBL
 + LockPool B CS_POOL_HEADER + CS_POOL_SIZE
 +</code>
 +
 +
 +\\
 +**Unit initialization:**
 +<code QCL>
 +;===
 +; Initialize system
 +;
 +GLOBAL
 + Initialized F OUT
 +
 +; main entry point
 +BEGIN
 + CALL TASK_INIT
 + WHILE TRUE
 + CALL TASK_EXECUTE
 + WAIT A_LOOP
 + ENDWHILE
 +END
 +
 +;===
 +; Task initialization
 +;
 +SUB TASK_INIT
 + SY10InitializeCriticalSection(LockPool)
 + Initialized = TRUE
 +ENDSUB
 +
 +;===
 +; Task execution
 +;
 +SUB TASK_EXECUTE
 + SUSPEND
 +ENDSUB
 +</code>
 +
 +=== Note ===
 +
 +  *The function must be performed only once during application initialization.
 +  *The [[software:qview:qview_6:qcl_library:sy10entercriticalsection|SY10EnterCriticalSection]] and [[software:qview:qview_6:qcl_library:sy10leavecriticalsection|SY10LeaveCriticalSection]] functions, should not be called before you have initialized the critical section with [[software:qview:qview_6:qcl_library:sy10initializecriticalsection|SY10InitializeCriticalSection]].