GETIFADDRS(3) | Library Functions Manual | GETIFADDRS(3) |
getifaddrs
,
freeifaddrs
— get interface
addresses
#include
<sys/types.h>
#include <sys/socket.h>
#include <ifaddrs.h>
int
getifaddrs
(struct
ifaddrs **ifap);
void
freeifaddrs
(struct
ifaddrs *ifap);
The
getifaddrs
()
function stores a reference to a linked list of the network interfaces on
the local machine in the memory referenced by ifap.
The list consists of ifaddrs structures, as defined in
the include file
<ifaddrs.h>
. The
ifaddrs structure contains at least the following
entries:
struct ifaddrs *ifa_next; /* Pointer to next struct */ char *ifa_name; /* Interface name */ u_int ifa_flags; /* Interface flags */ struct sockaddr *ifa_addr; /* Interface address */ struct sockaddr *ifa_netmask; /* Interface netmask */ struct sockaddr *ifa_broadaddr; /* Interface broadcast address */ struct sockaddr *ifa_dstaddr; /* P2P interface destination */ void *ifa_data; /* Address specific data */
NULL
in the last structure on the list.NULL
. (The sa_family field
of the ifa_addr field should be consulted to
determine the format of the ifa_addr address.)NULL
.NULL
.NULL
.AF_LINK
addresses it contains a pointer to the
struct if_data (as defined in include file
<net/if.h>
) which contains
various interface attributes and statistics. For all other address
families, ifa_data is
NULL
.The data returned by
getifaddrs
()
is dynamically allocated and should be freed using
freeifaddrs
()
when no longer needed.
Upon successful completion, the value 0 is returned; otherwise the value -1 is returned and the global variable errno is set to indicate the error.
The getifaddrs
() may fail and set
errno for any of the errors specified for the library
routines ioctl(2),
socket(2),
malloc(3), or
sysctl(2).
The getifaddrs
() function first appeared
in BSDI BSD/OS. The function has been available on
OpenBSD since OpenBSD
2.7.
If both <net/if.h>
and <ifaddrs.h>
are being
included, <net/if.h>
must be
included before
<ifaddrs.h>
.
January 12, 2018 | OpenBSD-6.4 |