| CCMSGHDR | BSD cmsg header structure |
| CDRIVER_MODEM | Access structure of the Modem Driver |
| Cevr_access | Union for accessing the debug parameters |
| CEVR_ADDR | |
| Cfd_set | BSD fd_set structure |
| CHOSTENT | BSD Host Entry structure |
| CIN6_ADDR | Generic IPv6 Address structure |
| CIN6_ADDR.u | Union members for different data accesses |
| CIN_ADDR | Generic IPv4 Address structure |
| CIN_ADDR.u | Union members for different data accesses |
| CIN_ADDR.u.s_b | IP address, byte access |
| CIN_ADDR.u.s_w | IP address, unsigned short integer access |
| CIOVEC | BSD scatter/gather array of items |
| CMSGHDR | BSD message header structure |
| CNET_ADDR | Network Address IPv4/IPv6 capable |
| CNET_ADDR4 | Network Address IPv4 only |
| CNET_DHCP_OPTION_ITEM | DHCP Option Item |
| CNET_ETH_LINK_INFO | Ethernet link information |
| CNET_FS_TIME | FS Interface Time info |
| CNET_SMTP_MAIL | SMTP Email Descriptor |
| CNET_SMTP_MTA | SMTP Mail Transfer Agent Descriptor |
| CNET_SNMP_BYTE_STR | SNMP-MIB byte-string |
| CNET_SNMP_MIB_INFO | SNMP-MIB Entry information |
| CNET_WIFI_CONFIG | WiFi Configuration |
| CNET_WIFI_NET_INFO | WiFi Network information |
| CNET_WIFI_SCAN_INFO | WiFi Scan information |
| CSOCKADDR | Generic Socket Address structure |
| CSOCKADDR_IN | IPv4 Socket Address structure |
| CSOCKADDR_IN6 | IPv6 Socket Address structure |
| CSOCKADDR_STORAGE | Socket Address storage structure |
| Ctimeval | BSD timeval structure |