Hp-Vee And Labview; Standard Spi (Stdspi.dll) - HP 85097A User Manual

Electronic calibration system

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Software Programming Interface

HP-VEE and LabVIEW

This section describes the standard SPI used by HP-VEE and

LabVIEW.

A translation layer is included that allows the graphical programming

languages used by Hewlett-Packard's VEE and National Instrument's

LabVIEW to connect to OLE objects.

This layer converts traditional C-style parameters to and from the

BSTR types used by the SPI. The programmer's view of StdSpi.dll is

that it implements the exact functionality of ECalSPI.dll, except the

functions are DLL-exports, and all BSTR parameters are C-string

pointers.

For example, the ECalSPI.dll implements the following OLE function

(or method):

long ECAL_FINT (BSTR*strOnOff,BSTR*strReturn);

In the StdSpi.dll, the function is:

long Ecal_Fint(unsigned char*strOnOff,unsigned char*strReturn);

Consider letter case for StdSpi.dll function names

StdSpi.dll function names are case-sensitive. In the OLE object,

function names are all capitals. The standard SPI uses the same

names, but only initial-capital letters in each word.

All StdSpi functions use the Pascal calling convention, _stdcall and

are exported from the 32 bit 'StdSpi.dll'. For example:

The function in ECalSPI (OLE) is:

long SENS_CORR_COLL_ACQ (BSTR*strModule);

The stdcall function in StdSpi.dll is:

long Sens_Corr_Coll_Acq (unsigned char*strModule);

The use of the standard SPI is demonstrated in the VEE and LabVIEW

examples of the directory, <root ecal>\examples\cpp. The standard

SPI can also be used by programmers unfamiliar with OLE or who wish

to interface the SPI from software that does not support OLE. You can

ﬁnd many examples of accessing exported DLL functions in the

compiler literature.

Chapter 3

3-15

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