endnetent(3p) — Linux manual page

ENDNETENT(3P)           POSIX Programmer's Manual          ENDNETENT(3P)

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

       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 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.

       The application shall not modify the structure to which the
       return value points, nor any storage areas pointed to by pointers
       within the structure. The returned pointer, and pointers within
       the structure, might be invalidated or the structure or the
       storage areas might be overwritten by a subsequent call to
       getnetbyaddr(), getnetbyname(), or getnetent().  The returned
       pointer, and pointers within the structure, might also be
       invalidated if the calling thread is terminated.

ERRORS

       No errors are defined.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       The Base Definitions volume of POSIX.1‐2017, netdb.h(0p)

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 .

IEEE/The Open Group               2017                     ENDNETENT(3P)

Pages that refer to this page: netdb.h(0p), getnetbyaddr(3p), inet_addr(3p), setnetent(3p)

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