In my QT application, I want to have it so some real-time information prints in the terminal if I run the application from the terminal.
When I use printf(\"print this\"
Qt doesn't interfere with printf output. (On Windows qmake (not Qt) does, but that doesn't apply to Linux). However, consider that the buffering behavior for stdout leads to printf("print this") not being printed until the buffer is flushed. Try with e.g. fflush(stdout) or simply append a newline: printf("print this\n") to have the buffer flushed. That's not related to Qt at all though.