The structure

enum RFC_MODE {

provides a type of connection to be openend by RfcOpen.

This structure is defined in SAPRFC.H.


·        RFC_MODE_R3ONLY

Use R/3 protocol and addressing scheme. Only for SAP systems. Any kind of user-ID (dialog user-ID, cpic user-ID) is possible.

connopt must point to a structure of type RFC_CONNOPT_R3ONLY.

·        RFC_MODE_CPIC

Use R/2 protocol and addressing scheme. Must be used for R/2, only cpic user-IDs are allowed. Since an SAP system is also capable of understanding the R/2 RFC protocol, you can also reach an SAP system with that mode. However, you must use a ‘sideinfo’ file for addressing.

connopt must point to a structure of type RFC_CONNOPT_CPIC.


Use R/3 protocol version 3. The receiving SAP System must have at least Release 3.0C to be able to serve every kind of options.

connopt must point to a structure of type RFC_CONNOPT_VERSION_3.


Use R/3 protocol version 3 or R/2 protocol and addressing scheme. This mode includes all three modes above and all necessary parameters will be read from an INI-file (saprfc.ini). See The SAPRFC.INI File for more details.

destination must point to a valid entry in the saprfc.ini. This file can be in the current directory where RFC programs are running or it must be defined by the environment variable RFC_INI (e.g. in /usr/rfctest/saprfc.ini).

connopt must be set to NULL.