if_nametoindex(3) Library Functions Manual if_nametoindex(3) if_nametoindex, if_indextoname - (libc -lc) #include unsigned int if_nametoindex(const char *ifname); char *if_indextoname(unsigned int ifindex, char *ifname); if_nametoindex() ifname. if_indextoname() ifindex. ifname. IF_NAMESIZE . if_nametoindex() 0 errno . if_indextoname() ifname NULL errno . if_nametoindex() errno : ENODEV . if_indextoname() errno : ENXIO . if_nametoindex() if_indextoname() socket(2) ioctl(2). attributes(7). +------------+------------------------------------+--------------------+ || | | +------------+------------------------------------+--------------------+ |if_nametoindex()| | MT-Safe | |if_indextoname()| | | +------------+------------------------------------+--------------------+ POSIX.1-2008, RFC 3493. POSIX.1-2001. BSDi. getifaddrs(3) if_nameindex(3) ifconfig(8) 3 . . : . 6.18 8 2026 if_nametoindex(3)