340 Chapter 5
Programming Fundamentals
Programming in C Using the VTL
Programming Fundamentals
The following is an example of opening a device session with the GPIB
device at primary address23.
ViSession defaultRM, vi;
.
.
viOpenDefaultRM (&defaultRM);
viOpen (defaultRM, "GPIB0::23::INSTR", VI_NULL,VI_NULL,&vi);
.
.
viClose(vi);
viClose (defaultRM);
Closing a Session
The viClose function must be used to close each session. You can close
the specific device session, which will free all data structures that had
been allocated for the session. If you close the default resource manager
session, all sessions opened using that resource manager will be closed.
Since system resources are also used when searching for resources
(viFindRsrc) or waiting for events (viWaitOnEvent), the viClose
function needs to be called to free up find lists and event contexts.