Chapter 3
103
Programming Examples
C Programming Examples using VTL
VXI2::128
Device at VXI logical address 128, in the third VXI system
(VXI2).
GPIB-VXI0::24 A VXI device at logical address 24. This VXI device is
connected via an GPIB/VXI command module.
GPIB0::7::0
An GPIB device at primary address 7 and secondary address 0
on the GPIB interface.
The following is an example of opening a device session with the GPIB device at
primary address 23.
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.
