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if_nameindex(3)         Library Functions Manual         if_nameindex(3)

ИМЯ

       if_nameindex, if_freenameindex - get network interface names and
       indexes

БИБЛИОТЕКА

       Standard C library (libc, -lc)

СИНТАКСИС

       #include <net/if.h>

       struct if_nameindex *if_nameindex(void);
       void if_freenameindex(struct if_nameindex *ptr);

ОПИСАНИЕ

       The if_nameindex() function returns an array of if_nameindex
       structures, each containing information about one of the network
       interfaces on the local system.  The if_nameindex structure
       contains at least the following entries:

           unsigned int if_index; /* Index of interface (1, 2, ...) */
           char        *if_name;  /* Null-terminated name ("eth0", etc.) */

       The if_index field contains the interface index.  The if_name
       field points to the null-terminated interface name.  The end of
       the array is indicated by entry with if_index set to zero and
       if_name set to NULL.

       The data structure returned by if_nameindex() is dynamically
       allocated and should be freed using if_freenameindex() when no
       longer needed.

ЗНАЧЕНИЕ, ВОЗВРАЩАЕМОЕ ФУНКЦИЕЙ

       On success, if_nameindex() returns pointer to the array; on
       error, NULL is returned, and errno is set to indicate the error.

ОШИБКИ

       if_nameindex() may fail and set errno if:

       ENOBUFS
              Insufficient resources available.

       if_nameindex() may also fail for any of the errors specified for
       socket(2), bind(2), ioctl(2), getsockname(2), recvmsg(2),
       sendto(2), or malloc(3).

АТРИБУТЫ

       For an explanation of the terms used in this section, see
       attributes(7).
       ┌─────────────────────────────────────┬───────────────┬─────────┐
       │ Interface                           │ Attribute     │ Value   │
       ├─────────────────────────────────────┼───────────────┼─────────┤
       │ if_nameindex(), if_freenameindex()  │ Thread safety │ MT-Safe │
       └─────────────────────────────────────┴───────────────┴─────────┘

СТАНДАРТЫ

       POSIX.1-2008, RFC 3493.

ИСТОРИЯ

       glibc 2.1.  POSIX.1-2001.  BSDi.

       Before glibc 2.3.4, the implementation supported only interfaces
       with IPv4 addresses.  Support of interfaces that don't have IPv4
       addresses is available only on kernels that support netlink.

ПРИМЕРЫ

       The program below demonstrates the use of the functions described
       on this page.  An example of the output this program might
       produce is the following:

           $ ./a.out
           1: lo
           2: wlan0
           3: em1

   Program source
       #include <net/if.h>
       #include <stdio.h>
       #include <stdlib.h>
       #include <unistd.h>

       int
       main(void)
       {
           struct if_nameindex *if_ni, *i;

           if_ni = if_nameindex();
           if (if_ni == NULL) {
               perror("if_nameindex");
               exit(EXIT_FAILURE);
           }

           for (i = if_ni; !(i->if_index == 0 && i->if_name == NULL); i++)
               printf("%u: %s\n", i->if_index, i->if_name);

           if_freenameindex(if_ni);

           exit(EXIT_SUCCESS);
       }

СМОТРИТЕ ТАКЖЕ

       getsockopt(2), setsockopt(2), getifaddrs(3), if_indextoname(3),
       if_nametoindex(3), ifconfig(8)

КОЛОФОН

       This page is part of the man-pages (Linux kernel and C library
       user-space interface documentation) project.  Information about
       the project can be found at 
       ⟨https://www.kernel.org/doc/man-pages/⟩.  If you have a bug report
       for this manual page, see
       ⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
       This page was obtained from the tarball man-pages-6.9.1.tar.gz
       fetched from
       ⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
       2024-06-26.  If you discover any rendering problems in this HTML
       version of the page, or you believe there is a better or more up-
       to-date source for the page, or you have corrections or
       improvements to the information in this COLOPHON (which is not
       part of the original manual page), send a mail to
       man-pages@man7.org

Linux man-pages 6.9.1          2024-06-15                if_nameindex(3)

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