F_VN_GetNumberOfElements

Gets the number of elements in the container. (Alternatively use interface method .getElementNum.)

Syntax

Definition:

FUNCTION F_VN_GetNumberOfElements : HRESULT
VAR_INPUT
    ipContainer       : ITcVnContainer;
END_VAR
VAR_IN_OUT
    nNumberOfElements : ULINT;
END_VAR
VAR_INPUT
    hrPrev            : HRESULT;
END_VAR

Inputs

Name	Type	Description
ipContainer	ITcVnContainer	Container
hrPrev	HRESULT	HRESULT indicating the result of previous operations (If SUCCEEDED(hrPrev) equals false, no operation is executed.)

In/Outputs

Name	Type	Description
nNumberOfElements	ULINT	Returns the number of elements in ipContainer

Return value

HRESULT

Further information

This function should not be used to iterate over the elements of a container. Use iterators to access the elements instead. In particular, the following code construct is not recommended:

hr := F_VN_GetNumberOfElements(ipContainer, ipNumber, hr);
FOR i:=0 TO (ipNumber-1) DO
    // access container elements
END_FOR

Since ipNumber is a UDINT (natural integer), a return value of ipNumber = 0 would cause an underflow.

Required License

TC3 Vision Base