Better use the call RfcOpenEx.

The following function opens an RFC connection.

RFC_HANDLE SAP_API RfcOpenExtV3(char* destination,
RFC_MODE mode,
char* hostname,
int sysnr,
char* gateway_host,
char* gateway_service,
char* client,
char* user,
char* password,
char* language,
int trace
RFC_INT use_load_balancing,
char * lb_host,
char * lb_system_name
char * lb_group
RFC_INT use_sapgui);

All parameters are passed as single fields (using RFC_MODE).

The following parameters are always needed in this call: RFC_MODE mode and SAP logon information: client, user, password, language, trace, and use_sapgui.

The following parameters are necessary, depending on RFC_MODE:

destination, gateway_host, gateway_service, hostname and sysnr will not be evaluated.

lb_host and lb_system_name must be defined. If lb_group is NULL, the group ‘PUBLIC’ will be used.

use_sapgui and ABAP-Debug are only available with R/3 3.0C or later and not on Windows with a 16-bit-RFC-library.

use_sapgui and ABAP-Debug are not available with R/2.

This function is defined in SAPRFC.H.

Return Values:

Function Parameters:

See also RfcOpen and RFC_OPTIONS.