Here is the code, but it doesn't work, can anybody help?
main()
{
status = viOpenDefaultRM(&defaultRM);
status = viOpen(defaultRM, "GPIB0::18::INSTR", VI_NULL, VI_NULL, &viSA);
viSetAttribute(viSA, VI_ATTR_TMO_VALUE, 20000);
viClear(viSA);
viInstallHandler(viSA, VI_EVENT_SERVICE_REQ, myCallback, bufferHandle);
viInstallHandler(viSA, VI_EVENT_IO_COMPLETION, myCallback, bufferHandle);
viEnableEvent(viSA, VI_EVENT_SERVICE_REQ, VI_HNDLR, VI_NULL);
viEnableEvent(viSA, VI_EVENT_IO_COMPLETION, VI_QUEUE, VI_NULL);
//start porform channel power measurement....
viPrintf(viSA, ":INITiate:CHPower\n");
status = viWaitOnEvent(viSA, VI_EVENT_IO_COMPLETION, 30000, &etype, &eventContext);
if (status < VI_SUCCESS) {
/* Waveform not received...exiting */
free(bufferHandle);
viClose(defaultRM);
return;
}
//try to fetch channel power here, but it never get there.
viPrintf(viSA, ":FETCH:CHP:CHP?\n");
viRead(viSA, (ViBuf)buf, 20, &numRead);
}
//callback
ViStatus _VI_FUNCH myCallback(ViSession vi, ViEventType etype, ViEvent eventContext, ViAddr userHandle)
{
ViJobId jobID;
ViStatus status;
ViUInt16 stb;
status = viReadSTB(vi, &stb);
status = viReadAsync(vi, (ViBuf)userHandle, 1024, &jobID);
return VI_SUCCESS;
}
