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

System Requirements

Development environment	Target platform	PLC libraries to include
TwinCAT V3.1.4024.54 or later	PC or CX (x64) with PL50, e.g. Intel 4-core Atom CPU	Tc3_Vision