User`s guide

Programming with VISA 3

Agilent VISA User’s Guide 71

return VI_SUCCESS;

}

void main(){

ViSession defaultRM,vi;

/* open session to VXI device */

viOpenDefaultRM(&defaultRM);

viOpen(defaultRM, "VXI0::24::INSTR", VI_NULL,

VI_NULL, &vi);

/* select trigger line TTL0 */

viSetAttribute(vi, VI_ATTR_TRIG_ID,

VI_TRIG_TTL0);

/* install the handler and enable it */

viInstallHandler(vi, VI_EVENT_TRIG, myHdlr,

(ViAddr)10);

viEnableEvent(vi, VI_EVENT_TRIG, VI_HNDLR,

VI_NULL);

/* fire trigger line, twice */

viAssertTrigger(vi, VI_TRIG_PROT_SYNC);

/* unenable and uninstall the handler */

viDisableEvent(vi, VI_EVENT_TRIG, VI_HNDLR);

viUninstallHandler(vi, VI_EVENT_TRIG, myHdlr,

(ViAddr)10);

/* close the sessions */

viClose(vi);

viClose(defaultRM);

}

Sample: SRQ Callback

This program installs an event handler and enables an SRQ

event. When the event occurs, the installed event handler is

called. This sample program is intended to show specific

VISA functionality and does not include error trapping.

Error trapping, however, is good programming practice and

is recommended in your VISA applications. See “Trapping

Errors” in this chapter for more information.