NAME

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

LIBRARY

     library “libnv”

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>