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Arduino-ESP32 Preference ライブラリ <不揮発性メモリへの読み書き>

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こちらのライブラリの内容確認です。(備忘)
https://github.com/espressif/arduino-esp32/tree/master/libraries/Preferences

exampleを見ると、Preferenceを指定した名前領域で開いたのち、その内部に各データを格納する。という流れの様です。
各関数はこんな感じです。

  • preferences.begin("my-app", false);
    • my-appというnamespaceで開始する。
  • preferences.clear();
    • 開かれているnamespace内のデータをすべて消去する。
  • preferences.remove("counter");
    • 開かれているnamespace内のcounterというデータのみを消去する。
  • preferences.end();
    • preferenceを閉じる

preference内へのデータの読み書きは、以下のようにput*** , get***,で読み書きできます。

putUInt("counter" , value);
getUInt("counter" , defaultValue);

格納できる型データは以下を参照してください。

Preferences.h
// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef _PREFERENCES_H_
#define _PREFERENCES_H_

#include "Arduino.h"

class Preferences {
    protected:
        uint32_t _handle;
        bool _started;
        bool _readOnly;
    public:
        Preferences();
        ~Preferences();

        bool begin(const char * name, bool readOnly=false);
        void end();

        bool clear();
        bool remove(const char * key);

        size_t putChar(const char* key, int8_t value);
        size_t putUChar(const char* key, uint8_t value);
        size_t putShort(const char* key, int16_t value);
        size_t putUShort(const char* key, uint16_t value);
        size_t putInt(const char* key, int32_t value);
        size_t putUInt(const char* key, uint32_t value);
        size_t putLong(const char* key, int32_t value);
        size_t putULong(const char* key, uint32_t value);
        size_t putLong64(const char* key, int64_t value);
        size_t putULong64(const char* key, uint64_t value);
        size_t putFloat(const char* key, float_t value);
        size_t putDouble(const char* key, double_t value);
        size_t putBool(const char* key, bool value);
        size_t putString(const char* key, const char* value);
        size_t putString(const char* key, String value);
        size_t putBytes(const char* key, const void* value, size_t len);

        int8_t getChar(const char* key, int8_t defaultValue = 0);
        uint8_t getUChar(const char* key, uint8_t defaultValue = 0);
        int16_t getShort(const char* key, int16_t defaultValue = 0);
        uint16_t getUShort(const char* key, uint16_t defaultValue = 0);
        int32_t getInt(const char* key, int32_t defaultValue = 0);
        uint32_t getUInt(const char* key, uint32_t defaultValue = 0);
        int32_t getLong(const char* key, int32_t defaultValue = 0);
        uint32_t getULong(const char* key, uint32_t defaultValue = 0);
        int64_t getLong64(const char* key, int64_t defaultValue = 0);
        uint64_t getULong64(const char* key, uint64_t defaultValue = 0);
        float_t getFloat(const char* key, float_t defaultValue = NAN);
        double_t getDouble(const char* key, double_t defaultValue = NAN);
        bool getBool(const char* key, bool defaultValue = false);
        size_t getString(const char* key, char* value, size_t maxLen);
        String getString(const char* key, String defaultValue = String());
        size_t getBytes(const char* key, void * buf, size_t maxLen);
};

#endif

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