12.7.2.7 Closed User Group

The user may set one of three types of Closed User Group facility: CUG_REQ (no outgoing access), CUG_REQ_ACS (with outgoing access), and CUG_BI (bilateral CUG). For CUG_REQ and CUG_REQ_ACS, the CUG is a decimal integer in the range 0-9999 (for 1980 X.25 interfaces, the valid range is 0-99). The extended form of the facility is used for CUG indices in the range 100-9999. This facility is set as follows:

u_short      cug_index;
 /* set cug_index to appropriate value */
 f.type = T_CUG;
 f.f_cug_req = CUG_REQ;    /* could be CUG_REQ_ACS or CUG_BI */
 f.f_cug_index = cug_index;
 error = ioctl(s, X25_SET_FACILITY, &f);
 

To read this facility:

f.type = T_CUG;
 error = ioctl(s, X25_GET_FACILITY, &f);
 cug_req = f.f_cug_req;
 cug_index = f.f_cug_index;