DNV(9)                 FreeBSD Kernel Developer's Manual                DNV(9)

NAME
     dnvlist_get, dnvlist_take - API for getting name/value pairs. Nonexistent
     pairs do not raise an error.

LIBRARY
     Name/value pairs library (libnv, -lnv)

SYNOPSIS
     #include <sys/dnv.h>

     bool
     dnvlist_get_bool(const nvlist_t *nvl, const char *name, bool defval);

     uint64_t
     dnvlist_get_number(const nvlist_t *nvl, const char *name,
         uint64_t defval);

     char *
     dnvlist_get_string(const nvlist_t *nvl, const char *name,
         const char *defval);

     nvlist_t *
     dnvlist_get_nvlist(const nvlist_t *nvl, const char *name,
         nvlist_t *defval);

     int
     dnvlist_get_descriptor(const nvlist_t *nvl, const char *name,
         int defval);

     void *
     dnvlist_get_binary(const nvlist_t *nvl, const char *name, size_t *sizep,
         void *defval, size_t defsize);

     bool
     dnvlist_take_bool(const nvlist_t *nvl, const char *name, bool defval);

     uint64_t
     dnvlist_take_number(const nvlist_t *nvl, const char *name,
         uint64_t defval);

     char *
     dnvlist_take_string(const nvlist_t *nvl, const char *name,
         const char *defval);

     nvlist_t *
     dnvlist_take_nvlist(const nvlist_t *nvl, const char *name,
         nvlist_t *defval);

     int
     dnvlist_take_descriptor(const nvlist_t *nvl, const char *name,
         int defval);

     void *
     dnvlist_take_binary(const nvlist_t *nvl, const char *name, size_t *sizep,
         void *defval, size_t defsize);

DESCRIPTION
     The libnv library permits easy management of name/value pairs and can
     send and receive them over sockets.  For more information, also see
     nv(9).

     The dnvlist_get family of functions returns the value associated with the
     specified name.  If an element of the specified name does not exist, the
     function returns the value provided in defval.  Returned strings,
     nvlists, descriptors, binaries, or arrays must not be modified by the
     user.  They still belong to the nvlist.  If the nvlist is in an error
     state, attempts to use any of these functions will cause the program to
     abort.

     The dnvlist_take family of functions returns the value associated with
     the specified name and removes the element from the nvlist.  If an
     element of the supplied name does not exist, the value provided in defval
     is returned.  When the value is a string, binary, or array value, the
     caller is responsible for freeing returned memory with free(3).  When the
     value is an nvlist, the caller is responsible for destroying the returned
     nvlist with nvlist_destroy().  When the value is a descriptor, the caller
     is responsible for closing the returned descriptor with close(2).

SEE ALSO
     close(2), free(3), nv(9)

HISTORY
     The dnv API appeared in FreeBSD 11.0.

AUTHORS
     The dnv API was implemented by Pawel Jakub Dawidek <pawel@dawidek.net>
     under sponsorship from the FreeBSD Foundation.  This manual page was
     written by Adam Starak <starak.adam@gmail.com>

FreeBSD 13.1-RELEASE-p6          July 26, 2016         FreeBSD 13.1-RELEASE-p6