PROLOG

       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of
       this interface may differ (consult the corresponding Linux  manual  page  for  details  of
       Linux behavior), or the interface may not be implemented on Linux.

NAME

       net/if.h — sockets local interfaces

SYNOPSIS

       #include <net/if.h>

DESCRIPTION

       The  <net/if.h>  header  shall  define  the if_nameindex structure, which shall include at
       least 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 shall define the following symbolic constant for  the  length  of  a
       buffer containing an interface name (including the terminating NULL character):

       IF_NAMESIZE Interface name length.

       The  following  shall be declared as functions and may also be defined as macros. Function
       prototypes shall be provided.

           void                  if_freenameindex(struct if_nameindex *);
           char                 *if_indextoname(unsigned, char *);
           struct if_nameindex  *if_nameindex(void);
           unsigned              if_nametoindex(const char *);

       The following sections are informative.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       The  System  Interfaces  volume  of  POSIX.1‐2017,  if_freenameindex(),  if_indextoname(),
       if_nameindex(), if_nametoindex()

COPYRIGHT

       Portions  of  this  text  are  reprinted  and  reproduced in electronic form from IEEE Std
       1003.1-2017, Standard for Information Technology -- Portable  Operating  System  Interface
       (POSIX),  The  Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by
       the Institute of Electrical and Electronics Engineers, Inc and The  Open  Group.   In  the
       event  of  any  discrepancy  between this version and the original IEEE and The Open Group
       Standard, the original IEEE and The Open Group  Standard  is  the  referee  document.  The
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

       Any  typographical  or  formatting errors that appear in this page are most likely to have
       been introduced during the conversion of the source files to man page  format.  To  report
       such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .