#include "visa.h"
#include <stdlib.h>

#define MAX_CNT 1024

/* This function is to be called when an SRQ event occurs */
/* Here, an SRQ event indicates the device has data ready */
ViStatus _VI_FUNCH myCallback(ViSession vi, ViEventType etype, ViEvent eventContext, ViAddr userHandle)
{

}

int main(void)
{

/* Error initializing VISA...exiting */
return -1;

}
/* Open communication with GPIB device at primary address 2 */
status = viOpen(defaultRM, "GPIB0::2::INSTR", VI_NULL, VI_NULL, &gpibSesn);

/* Allocate memory for buffer */
/* In addition, allocate space for the ASCII NULL character */
bufferHandle = (ViBuf)malloc(MAX_CNT+1);

/* Tell the driver what function to call on an event */
status = viInstallHandler(gpibSesn, VI_EVENT_SERVICE_REQ, myCallback, bufferHandle);

/* Enable the driver to detect events */
status = viEnableEvent(gpibSesn, VI_EVENT_SERVICE_REQ, VI_HNDLR, VI_NULL);
status = viEnableEvent(gpibSesn, VI_EVENT_IO_COMPLETION, VI_QUEUE, VI_NULL);

/* Tell the device to begin acquiring a waveform */
status = viWrite(gpibSesn, "E0x51; W1", 9, &retCount);

/* The device asserts SRQ when the waveform is ready */
/* The callback begins reading the data */
/* After the data is read, an I/O completion event occurs */

status = viWaitOnEvent(gpibSesn, VI_EVENT_IO_COMPLETION, 20000, &etype, &eventContext);
if (status < VI_SUCCESS) {

/* Waveform not received...exiting */
free(bufferHandle);
viClose(defaultRM);
return -1;

}
/* Your code should process the waveform data */

/* Close the event context */
viClose(eventContext);

/* Stop listening for events */
status = viDisableEvent(gpibSesn, VI_ALL_ENABLED_EVENTS, VI_ALL_MECH);
status = viUninstallHandler(gpibSesn, VI_EVENT_SERVICE_REQ, myCallback,bufferHandle);

/* Close down the system */
free(bufferHandle);
status = viClose(gpibSesn);
status = viClose(defaultRM);
return 0;

}