if.h(3HEAD) Headers if.h(3HEAD)NAME
if.h, if - sockets local interfaces
SYNOPSIS
#include <net/if.h>
DESCRIPTION
The <net/if.h> header defines the if_nameindex structure, which includes the following members:
unsigned if_index /* numeric index of the interface */
char *if_name /* null-terminated name of the interface */
The <net/if.h> header defines the following macro for the length of a buffer containing an interface name (including the terminating null
character):
IF_NAMESIZE interface name length
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Interface Stability |Standard |
+-----------------------------+-----------------------------+
SEE ALSO if_nametoindex(3XNET), attributes(5), standards(5)SunOS 5.11 10 Sep 2004 if.h(3HEAD)
Check Out this Related Man Page
if_nametoindex(3XNET) X/Open Networking Services Library Functions if_nametoindex(3XNET)NAME
if_nametoindex, if_indextoname, if_nameindex, if_freenameindex - functions to map Internet Protocol network interface names and interface
indexes
SYNOPSIS
cc [ flag... ] file... -lxnet [ library... ]
#include <net/if.h>
unsigned int if_nametoindex(const char *ifname);
char *if_indextoname(unsigned int ifindex, char *ifname);
struct if_nameindex *if_nameindex(void)
void if_freenameindex(struct if_nameindex *ptr);
PARAMETERS
These functions support the following parameters:
ifname interface name
ifindex interface index
ptr pointer returned by if_nameindex()
DESCRIPTION
This API defines two functions that map between an Internet Protocol network interface name and index, a third function that returns all
the interface names and indexes, and a fourth function to return the dynamic memory allocated by the previous function.
Network interfaces are normally known by names such as eri0, sl1, ppp2, and the like. The ifname argument must point to a buffer of at
least IF_NAMESIZE bytes into which the interface name corresponding to the specified index is returned. IF_NAMESIZE is defined in
<net/if.h> and its value includes a terminating null byte at the end of the interface name.
if_nametoindex() The if_nametoindex() function returns the interface index corresponding to the interface name pointed to by the
ifname pointer. If the specified interface name does not exist, the return value is 0, and errno is set to ENXIO. If
there was a system error, such as running out of memory, the return value is 0 and errno is set to the proper value,
for example, ENOMEM.
if_indextoname() The if_indextoname() function maps an interface index into its corresponding name. This pointer is also the return
value of the function. If there is no interface corresponding to the specified index, NULL is returned, and errno is
set to ENXIO, if there was a system error, such as running out of memory, if_indextoname() returns NULL and errno
would be set to the proper value, for example, ENOMEM.
*if_nameindex() The if_nameindex() function returns an array of if_nameindex structures, one structure per interface. The if_namein-
dex structure holds the information about a single interface and is defined when the <net/if.h> header is included:
struct if_nameindex {
unsigned int if_index; /* 1, 2, ... */
char *if_name; /* null terminated name: "eri0", ... */
};
The end of the array of structures is indicated by a structure with an if_index of 0 and an if_name of NULL. The
function returns a null pointer upon an error and sets errno to the appropriate value. The memory used for this array
of structures along with the interface names pointed to by the if_name members is obtained dynamically. This memory
is freed by the if_freenameindex() function.
if_freenameindex() The if_freenameindex() function frees the dynamic memory that was allocated by if_nameindex(). The argument to this
function must be a pointer that was returned by if_nameindex().
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWcsl (32-bit) |
+-----------------------------+-----------------------------+
| |SUNWcslx (64-bit) |
+-----------------------------+-----------------------------+
|Interface Stability |Standard |
+-----------------------------+-----------------------------+
|MT-Level |MT-Safe |
+-----------------------------+-----------------------------+
SEE ALSO ifconfig(1M), if_nametoindex(3SOCKET), attributes(5), standards(5), if(7P)SunOS 5.11 14 Dec 2003 if_nametoindex(3XNET)