CNV(9) | Kernel Developer's Manual | CNV(9) |
NAME¶
cnvlist_get
, cnvlist_take
,
cnvlist_free
—
LIBRARY¶
Name/value pairs library (libnv, -lnv)SYNOPSIS¶
#include <sys/cnv.h>
const char *
cnvlist_name
(const
void *cookie);
int
cnvlist_type
(const
void *cookie);
bool
cnvlist_get_bool
(const
void *cookie);
uint64_t
cnvlist_get_number
(const
void *cookie);
const char *
cnvlist_get_string
(const
void *cookie);
const nvlist_t *
cnvlist_get_nvlist
(const
void *cookie);
const void *
cnvlist_get_binary
(const
void *cookie, size_t
*sizep);
const bool *
cnvlist_get_bool_array
(const
void *cookie, size_t
*nitemsp);
const uint64_t *
cnvlist_get_number_array
(const
void *cookie, size_t
*nitemsp);
const char * const *
cnvlist_get_string_array
(const
void *cookie, size_t
*nitemsp);
const nvlist_t * const *
cnvlist_get_nvlist_array
(const
void *cookie, size_t
*nitemsp);
int
cnvlist_get_descriptor
(const
void *cookie);
const int *
cnvlist_get_descriptor_array
(const
void *cookie, size_t
*nitemsp);
bool
cnvlist_take_bool
(void
*cookie);
uint64_t
cnvlist_take_number
(void
*cookie);
const char *
cnvlist_take_string
(void
*cookie);
const nvlist_t *
cnvlist_take_nvlist
(void
*cookie);
const void *
cnvlist_take_binary
(void
*cookie, size_t
*sizep);
const bool *
cnvlist_take_bool_array
(void
*cookie, size_t
*nitemsp);
const uint64_t *
cnvlist_take_number_array
(void
*cookie, size_t
*nitemsp);
const char * const *
cnvlist_take_string_array
(void
*cookie, size_t
*nitemsp);
const nvlist_t * const *
cnvlist_take_nvlist_array
(void
*cookie, size_t
*nitemsp);
int
cnvlist_take_descriptor
(void
*cookie);
const int *
cnvlist_take_descriptor_array
(void
*cookie, size_t
*nitemsp);
void
cnvlist_free_null
(void
*cookie);
void
cnvlist_free_bool
(void
*cookie);
void
cnvlist_free_number
(void
*cookie);
void
cnvlist_free_string
(void
*cookie);
void
cnvlist_free_nvlist
(void
*cookie);
void
cnvlist_free_descriptor
(void
*cookie);
void
cnvlist_free_binary
(void
*cookie);
void
cnvlist_free_bool_array
(void
*cookie);
void
cnvlist_free_number_array
(void
*cookie);
void
cnvlist_free_string_array
(void
*cookie);
void
cnvlist_free_nvlist_array
(void
*cookie);
void
cnvlist_free_descriptor_array
(void
*cookie);
DESCRIPTION¶
Thelibnv
library permits easy management of name/value
pairs and can send and receive them over sockets. For more information, also
see nv(9).
The concept of cookies is explained in
nvlist_next
(),
nvlist_get_parent
(), and
nvlist_get_pararr
() from
nv(9).
The cnvlist_name
() function returns the
name of an element associated with the given cookie.
The cnvlist_type
() function returns the
type of an element associated with the given cookie. Types which can be
returned are described in nv(9).
The cnvlist_get
family of functions
obtains the value associated with the given cookie. Returned strings,
nvlists, descriptors, binaries, or arrays must not be modified by the user,
since they still belong to the nvlist. The nvlist must not be in an error
state.
The cnvlist_take
family of functions
returns the value associated with the given cookie and removes the element
from the nvlist. When the value is a string, binary, or array value, the
caller is responsible for freeing the 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 the
close
(2).
The cnvlist_free
family of functions
removes an element of the supplied cookie and frees all resources. If an
element of the given cookie has the wrong type or does not exist, the
program is aborted.
EXAMPLE¶
The following example demonstrates how to deal with cnvlist API.int type; void *cookie, *scookie, *bcookie; nvlist_t *nvl; char *name; nvl = nvlist_create(0); nvlist_add_bool(nvl, "test", 1 == 2); nvlist_add_string(nvl, "test2", "cnvlist"); cookie = NULL; while (nvlist_next(nvl, &type, &cookie) != NULL) { switch (type) { case NV_TYPE_BOOL: printf("test: %d\n", cnvlist_get_bool(cookie)); bcookie = cookie; break; case NV_TYPE_STRING: printf("test2: %s\n", cnvlist_get_string(cookie)); scookie = cookie; break; } } name = cnvlist_take_string(scookie); cnvlist_free_bool(bcookie); printf("test2: %s\n", name); free(name); printf("nvlist_empty = %d\n", nvlist_empty(nvl)); nvlist_destroy(nvl); return (0);
SEE ALSO¶
close(2), free(3), nv(9)AUTHORS¶
Thecnv
API was created during the Google Summer Of Code
2016 by Adam Starak.
June 18, 2018 | Linux 4.19.0-10-amd64 |