Agilent Technologies FS2010 Guide de l'utilisateur télécharger pdf (Page 66)

66 Agilent VISA User’s Guide

3 Programming with VISA

ViStatus _VI_FUNCH my_handler (ViSession vi,

ViEventType eventType, ViEvent context, ViAddr

usrHandle) {

/* your event handling code here */

return VI_SUCCESS;

}

main(){

ViSession vi;

ViAddr addr=0;

viInstallHandler(vi, VI_EVENT_SERVICE_REQ,

my_handler, addr);

viEnableEvent(vi, VI_EVENT_SERVICE_REQ,

VI_HNDLR, VI_NULL);

/* your code here */

viDisableEvent(vi, VI_EVENT_SERVICE_REQ,

VI_HNDLR);

viUninstallHandler(vi, VI_EVENT_SERVICE_REQ,

my_handler, addr);

}

Installing Handlers

VISA allows applications to install multiple handlers for an

event type on the same session. Multiple handlers can be

installed through multiple invocations of the

viInstallHandler operation, where each invocation adds to

the previous list of handlers.

If more than one handler is installed for an event type, each

of the handlers is invoked on every occurrence of the

specified event(s). VISA specifies that the handlers are

invoked in Last In First Out (LIFO) order. Use the following

function when installing an event handler:

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Agilent Technologies FS2010 Guide de l'utilisateur Page 66