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doc (nvs): added note about maximum possible namespaces

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This commit is contained in:
Jakob Hasse 2022-08-23 17:10:16 +02:00
parent 6d7877fcb8
commit 87ff108235
2 changed files with 5 additions and 1 deletions
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4
components/nvs_flash/include/nvs.h
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@ -132,6 +132,8 @@ typedef struct nvs_opaque_iterator_t *nvs_iterator_t;
* mode is NVS_READONLY
* - ESP_ERR_NVS_INVALID_NAME if namespace name doesn't satisfy constraints
* - ESP_ERR_NO_MEM in case memory could not be allocated for the internal structures
* - ESP_ERR_NVS_NOT_ENOUGH_SPACE if there is no space for a new entry or there are too many different
* namespaces (maximum allowed different namespaces: 254)
* - other error codes from the underlying storage driver
*/
esp_err_t nvs_open(const char* name, nvs_open_mode_t open_mode, nvs_handle_t *out_handle);
@ -161,6 +163,8 @@ esp_err_t nvs_open(const char* name, nvs_open_mode_t open_mode, nvs_handle_t *ou
* mode is NVS_READONLY
* - ESP_ERR_NVS_INVALID_NAME if namespace name doesn't satisfy constraints
* - ESP_ERR_NO_MEM in case memory could not be allocated for the internal structures
* - ESP_ERR_NVS_NOT_ENOUGH_SPACE if there is no space for a new entry or there are too many different
* namespaces (maximum allowed different namespaces: 254)
* - other error codes from the underlying storage driver
*/
esp_err_t nvs_open_from_partition(const char *part_name, const char* name, nvs_open_mode_t open_mode, nvs_handle_t *out_handle);

2
docs/en/api-reference/storage/nvs_flash.rst
View File

@ -46,7 +46,7 @@ Data type check is also performed when reading a value. An error is returned if
Namespaces
^^^^^^^^^^
To mitigate potential conflicts in key names between different components, NVS assigns each key-value pair to one of namespaces. Namespace names follow the same rules as key names, i.e., the maximum length is 15 characters. Namespace name is specified in the :cpp:func:`nvs_open` or :cpp:type:`nvs_open_from_partition` call. This call returns an opaque handle, which is used in subsequent calls to the ``nvs_get_*``, ``nvs_set_*``, and :cpp:func:`nvs_commit` functions. This way, a handle is associated with a namespace, and key names will not collide with same names in other namespaces. Please note that the namespaces with the same name in different NVS partitions are considered as separate namespaces.
To mitigate potential conflicts in key names between different components, NVS assigns each key-value pair to one of namespaces. Namespace names follow the same rules as key names, i.e., the maximum length is 15 characters. Furthermore, there can be no more than 254 different namespaces in one NVS partition. Namespace name is specified in the :cpp:func:`nvs_open` or :cpp:type:`nvs_open_from_partition` call. This call returns an opaque handle, which is used in subsequent calls to the ``nvs_get_*``, ``nvs_set_*``, and :cpp:func:`nvs_commit` functions. This way, a handle is associated with a namespace, and key names will not collide with same names in other namespaces. Please note that the namespaces with the same name in different NVS partitions are considered as separate namespaces.
NVS iterators
^^^^^^^^^^^^^