Using Sessions

Using Sessions

This section shows how to use VISA sessions, including:

• Opening a Session
• Addressing a Session
• Closing a Session
• Searching for Resources

Including the VISA Declarations File (C/C++)

For C and C++ programs, you must include the visa.h header file at the beginning of every file that contains VISA function calls:

#include "visa.h"

This header file contains the VISA function prototypes and the definitions for all VISA constants and error codes. The visa.h header file also includes the visatype.h header file.

The visatype.h header file defines most of the VISA types. The VISA types are used throughout VISA to specify data types used in the functions. For example, the viOpenDefaultRM function requires a pointer to a parameter of type ViSession. If you find ViSession in the visatype.h header file, you will find that ViSession is eventually typed as an unsigned long.

Adding the visa32.bas File (Visual Basic)

You must add the visa32.bas Basic module file to your Visual Basic project. The visa32.bas file contains the VISA function prototypes and definitions for all VISA constants and error codes.