> Hi,
>  I'm a little confused about the "call operation action" of
> activity diagram of SysML. Below is what i understand about
> the call operation action and what i don't understand. Please
> correct me if necessary and answer my question.

> Call operation action is used to invoke a operation (or
> function) defined  in a "block definition diagram" or a
> pre-defined operation in sysml. Input pins (attached to
> callOperationAction node) can be used to specify the
> arguments (parameters) passed to the operation. The output
> pins represent the results obtained from the operation. There
> can be any number of input and output pins attached to the
> call operaton action node.
> I don't understand the use of the "target" input pin which
> needs to be present to make a valid call opertaion action.
> Please somebody explain what is the purpose of having the
> target input pin and what does it signify?

> Thanks in advance,
> Vikas Patel