C++ 使用 Arduino 将字符串转换为 const char* 类型
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convert String to type const char* using Arduino
提问by Caustic
I am using the Arduino library. I would like to log some data from a sensor, date-time stamp it and write it to a SD card.
我正在使用 Arduino 库。我想从传感器记录一些数据，为其添加日期时间戳并将其写入 SD 卡。
To build the text file name I have tried
要构建我尝试过的文本文件名
String dataFileName = String(String(sedClock.getTime().year(),DEC) +
String(sedClock.getTime().month(),DEC) +
String(sedClock.getTime().day(),DEC) +
String(sedClock.getTime().hour(),DEC) +
String(sedClock.getTime().minute(),DEC) +
String(sedClock.getTime().second(),DEC) + '_log.txt');
I would then like to log to that file using
然后我想使用登录到该文件
pinMode(SD_PIN,OUTPUT);
dataFile = SD.open(dataFileName,FILE_WRITE);
But I get
但我得到
no matching function call to SDClass::open(String&, int)
candidates are: File SDClass::open(const char*,uint_8)
But it seems that Arduino string doesn't have the equivalent of
但似乎 Arduino 字符串没有相当于
(const char *) dataFileName.c_str()
So I can't figure out how to do the correct conversion
所以我不知道如何进行正确的转换
Any help would be greatly appreciated.
任何帮助将不胜感激。
回答by Caustic
Thanks for your help. The solution was
谢谢你的帮助。解决办法是
char __dataFileName[sizeof(dataFileName)];
dataFileName.toCharArray(__dataFileName, sizeof(__dataFileName));
pinMode(SD_PIN,OUTPUT);
dataFile = SD.open(__dataFileName,FILE_WRITE);
回答by ForEveR
How about StringToCharArrayor StringGetBytes?
