Jack Douglas asked 3 months ago
I am following instructions in part using an SD Card as described here https://randomnerdtutorials.com/esp32-microsd-card-arduino/ on an esp32. Sensor data is written to the card, then it is later opened and the data is sent. Once it is sent, I want to clear the contents. However, if I use SD.remove(“/data.txt”) the data is cleared, but the following error occurs :
[ 27102][E][vfs_api.cpp:104] open(): /sd/data.txt does not exist, no permits for creation
End Data
[ 29103][E][vfs_api.cpp:175] remove(): /data.txt does not exists or is directory
How to avoid this from occurring?
I guess I could delete the file altogether and create it again each time the program runs. Seems like there should be a simple way to clear the contents.
Sara Santos Staff answered 3 months ago
Hi.
Can you try the following snippet? It opens the file, moves the cursor to the beginning of the file, removes all contents, and closes the file. I didn’t test it.
File file = SD.open("data.txt", FILE_WRITE);
file.seek(0);
file.truncate();
file.close();
Tell me if it works.
Regards,
Sara
Jack Douglas answered 3 months ago
The following error occurs :
on_120822TEST.ino:389:30: error: 'class fs::File' has no member named 'truncate'
dataFile.truncate();
^~~~~~~~
*** [.pio\build\esp32dev\src\SoilStation_120822TEST.ino.cpp.o] Error 1
Jack Douglas answered 2 months ago
As per my initial thoughts, I ended up using SD.remove() [https://arduinogetstarted.com/reference/library/arduino-sd.remove], then creating a new file for each loop.
Sara Santos Staff answered 2 months ago
Hi.
I’m so sorry for taking so long to get back to you.
For some reason, I didn’t receive a notification from your previous response.
Thanks for sharing that solution.
Regards,
Sara
Sara Santos Staff answered 2 months ago
I’ll mark this issue as resolved. If you need further help, you just need to open a new question in our forum.
Regards,
Sara