NAME

       endnetent, getnetbyaddr, getnetbyname, getnetent, setnetent - network database functions

SYNOPSIS

       #include <netdb.h>

       void endnetent(void);
       struct netent *getnetbyaddr(uint32_t net, int type);
       struct netent *getnetbyname(const char *name);
       struct netent *getnetent(void);
       void setnetent(int stayopen);

DESCRIPTION

       These  functions shall retrieve information about networks. This information is considered
       to  be  stored  in  a  database  that  can  be  accessed  sequentially  or  randomly.  The
       implementation of this database is unspecified.

       The  setnetent() function shall open and rewind the database.  If the stayopen argument is
       non-zero, the connection to the net database shall  not  be  closed  after  each  call  to
       getnetent() (either directly, or indirectly through one of the other getnet*() functions),
       and the implementation may maintain an open file descriptor to the database.

       The getnetent() function shall read the next entry of the database, opening and closing  a
       connection to the database as necessary.

       The  getnetbyaddr()  function  shall  search the database from the beginning, and find the
       first entry for which the address family specified by type matches the  n_addrtype  member
       and  the  network number net matches the n_net member, opening and closing a connection to
       the database as necessary.  The net argument shall be the  network  number  in  host  byte
       order.

       The  getnetbyname()  function  shall  search  the database from the beginning and find the
       first entry for which the network name  specified  by  name  matches  the  n_name  member,
       opening and closing a connection to the database as necessary.

       The  getnetbyaddr(), getnetbyname(), and getnetent() functions shall each return a pointer
       to a netent structure, the members of which shall contain the fields of an  entry  in  the
       network database.

       The endnetent() function shall close the database, releasing any open file descriptor.

       These  functions need not be reentrant. A function that is not required to be reentrant is
       not required to be thread-safe.

RETURN VALUE

       Upon successful completion, getnetbyaddr(), getnetbyname(), and getnetent() shall return a
       pointer  to a netent structure if the requested entry was found, and a null pointer if the
       end of the database was reached or the requested entry was not found.  Otherwise,  a  null
       pointer shall be returned.

ERRORS

       No errors are defined.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       The  getnetbyaddr(),  getnetbyname(),  and  getnetent()  functions  may return pointers to
       static data, which may be overwritten by subsequent calls to any of these functions.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       The Base Definitions volume of IEEE Std 1003.1-2001, <netdb.h>

COPYRIGHT

       Portions of this text are reprinted and  reproduced  in  electronic  form  from  IEEE  Std
       1003.1,  2003  Edition,  Standard  for Information Technology -- Portable Operating System
       Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003  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 .