Dear Bartosz First of all thank you for gpiomon software. I try to use if for data acquisition from an optical sensor. It works fine from command line but when I try to run it as QProcess in QT (GUI) there is a problem with buffering. The output is transferred occasionally in large pieces. What I need is to get output immediately after each line. I plan to distribute my software as open source. As I understand this problem can be solved by adding to your code setbuf(stdout, NULL); or fflush(stdout) after each line. I hope you will be able to help me with this. Best wishes Adam Adam Tofilski Department of Zoology and Animal Welfare Agricultural University 29 Listopada 56 31-425 Krakow Poland rotofils@xxxxxxxxxxxxx tel: +48 12 6625069