NAME
ifnametoindex, ifindextoname - mappings between network interface names and indexes SYNOPSIS
#include
unsigned int ifnametoindex(const char *ifname); char *ifindextoname(unsigned int ifindex, char *ifname); DESCRIPTION The ifnametoindex() function returns the index of the network inter‐ face corresponding to the name ifname. The ifindextoname() function returns the name of the network interface corresponding to the interface index ifindex. The name is placed in the buffer pointed to by ifname. The buffer must allow for the storage of at least IFNAMESIZE bytes. RETURN VALUE On success, ifnametoindex() returns the index number of the network interface; on error, 0 is returned and errno is set appropriately. On success, ifindextoname() returns ifname; on error, NULL is returned and errno is set appropriately. ERRORS ifindextoname() may fail and set errno if: ENXIO No interface found for the index. ifnametoindex() and ifindextoname() may also fail for any of the errors specified for socket(2) or ioctl(2). ATTRIBUTES For an explanation of the terms used in this section, see attributes(7). ┌───────────────────────────────────┬───────────────┬─────────┐ │Interface │ Attribute │ Value │ ├───────────────────────────────────┼───────────────┼─────────┤ │ifnametoindex(), ifindextoname() │ Thread safety │ MT-Safe │ └───────────────────────────────────┴───────────────┴─────────┘ CONFORMING TO
RFC 3493, POSIX.1-2001. This function first appeared in BSDi. SEE ALSO getifaddrs(3), ifnameindex(3), ifconfig(8) COLOPHON
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GNU 2012-12-14 IFNAMETOINDEX(3)