Agilent Technologies E2094S, User Manual, Page: 77 / 146

Programming with VISA
3
Agilent VISA User’s Guide 77
/* Print results */
printf ("Instrument identification string:
%s\n", buf);
/* Close session */
viClose (vi);
viClose (defaultRM);}
Example: Shared Lock This example shows a session gaining a
shared lock with the accessKey called lockkey . Other sessions can now
use this accessKey in the requestedKey parameter of the viLock
function to share access on the locked resource. This example then
shows the original session acquiring an exclusive lock while
maintaining its shared lock.
When the session holding the exclusive lock unlocks the resource via
the
viUnlock function, all the sessions sharing the lock again have all
the access privileges associated with the shared lock.
/* lockshr.c
This example program queries a GPIB device for
an identification string and prints the results.
Note that you must change the address. */
#include <visa.h>
#include <stdio.h>
void main () {
ViSession defaultRM, vi;
char buf [256] = {0};
char lockkey [256] = {0};
/* Open session to GPIB device at address 22 */
viOpenDefaultRM (&defaultRM);
viOpen (defaultRM, "GPIB0::22::INSTR",
VI_NULL,VI_NULL,&vi);
/* acquire a shared lock so only this process
and processes that we know about can access
this resource */
viLock (vi, VI_SHARED_LOCK, 2000, VI_NULL,
lockkey);