@JonB
I changed it as you said and it works well!!!

@J-Hilk thank you

@suslucoder said in no member named 'write' in 'QString':

Im on ubuntu

:) Oh, OK, then it doesn't actually matter as there is no "text vs binary" mode/format under Linux! Nonetheless I think it's good practice to put QIODevice::Text in, just in case you ever port to Windows...

@KroMignon thank you

@aha_1980 I'm expecting to read and write data with a serial port, but, for some reason, the data sent by my pc is also read by my pc, so the problems is that the data sent is somehow triggering the readyRead signals.

@J-Hilk I noticed that ,effectively, the echo wasn't turned off on the pi. For whatever reason, it completely broke my programs when I'm turning it of, so I'm going to install qt and try again on the pi before calling it a win.

Writing a newline separately works, as suggested by micland. Thanks guys!

Here is the code:

QFile file("testfile"); if(file.open(QIODevice::ReadWrite | QIODevice::Text)) { QByteArray buf("Hello "); buf += file.readAll(); file.seek(0); file.write(buf); } else qDebug() << "error reading file";

BUT it's not truncating the old content so the new content have to be bigger than the old one. If your second content could be smaller, just take the approach with a second file...
Why don't you just append it to the end of the file?

Cheers
AlexRoot

@NetZwerg
I have set the values previously.

if(var == "TR") { filter_values[row][column] = 0; }

AFAIC Qt Creator assumes that examples are self contained. These are a bit of a special case

@yoavmil I have been searching many forum and what was missing for me was the setDataTerminalReady(true);

Finaly, it is working now!

@sneubert

Works perfectly! I've made the mistake to add it over an comma. Thanks!