create_conditioncreate_conditioncreate_conditionCreateConditionCreateCondition (Operator)

Name

create_conditioncreate_conditioncreate_conditionCreateConditionCreateCondition — Create a condition variable synchronization object.

Signature

create_condition( : : AttribName, AttribValue : ConditionHandle)

A condition variable (short: “condition”) is a synchronization device that allows threads to suspend execution and relinquish the processors until some predicate on shared data is satisfied. The basic operations on conditions are: signal the condition (when the predicate becomes true), and wait for the condition, suspending the thread execution until another thread signals the condition.

A condition variable must always be associated with a mutex, to avoid the race condition where a thread prepares to wait on a condition variable and another thread signals the condition just before the first thread actually waits on it.

create_conditioncreate_conditioncreate_conditionCreateConditionCreateCondition creates and initializes the condition variable ConditionHandleConditionHandleConditionHandleConditionHandleconditionHandle, using the condition attributes specified in AttribNameAttribNameAttribNameAttribNameattribName and AttribValueAttribValueAttribValueAttribValueattribValue, or default attributes if AttribNameAttribNameAttribNameAttribNameattribName is ''"""""""". The current implementation supports no attributes for conditions, hence the AttribNameAttribNameAttribNameAttribNameattribName parameter must be set to ''"""""""".

Parallelization

Multithreading type: independent (runs in parallel even with exclusive operators).
Multithreading scope: global (may be called from any thread).
Processed without parallelization.

Parameters

AttribNameAttribNameAttribNameAttribNameattribName (input_control) number(-array) → (string / integer / real)

Mutex attribute.

Default value: '' "" "" "" ""

AttribValueAttribValueAttribValueAttribValueattribValue (input_control) number(-array) → (string / integer / real)

Mutex attribute value.

Number of elements: AttribValue == AttribName

Default value: '' "" "" "" ""

ConditionHandleConditionHandleConditionHandleConditionHandleconditionHandle (output_control) condition → (integer)

Condition synchronization object.

Result

create_conditioncreate_conditioncreate_conditionCreateConditionCreateCondition returns 2 (H_MSG_TRUE) if all parameters are correct. If necessary, an exception is raised.

Possible Successors

wait_conditionwait_conditionwait_conditionWaitConditionWaitCondition, timed_wait_conditiontimed_wait_conditiontimed_wait_conditionTimedWaitConditionTimedWaitCondition, signal_conditionsignal_conditionsignal_conditionSignalConditionSignalCondition

Module

Foundation

Table of Contents / System / Multithreading

Operators

HALCON Reference Manual 10.0.2