Sending console to SPI displays? To write normally to /dev/tty0, make yourself a member of tty0's group tty, with: sudo usermod -a -G tty pi Log out and log in to make that take effect. You can now redirect any text or command output to /dev/tty0 and it will show on the screen. Feb 18, 2011 printf('SERIAL: Device%s is now closed.n', dev); In summary the Serial object can be created and used to read char values using.getChar. This seems to work fine however calling.getChar only sometimes contains the chars that I'm interested in and most of the time contains junk characters. I can send a file to it using 'cat commandfile.txt /dev/ttyUSB0' and the device reacts to the command as I expect. My problem is that I can't get my C code to communicate with it. I was trying to use fopen and fprinf to send my data but I'm not really sure that's what I should be using. Intro to File Input/Output in C. One way to get input into a program or to display output from a program is to use standard input and standard output, respectively. All that means is that to read in data, we use cin (or a few other functions) and to write out data, we use cout.
-->Syntax
Remarks
These are standard streams for input, output, and error output.
By default, standard input is read from the keyboard, while standard output and standard error are printed to the screen.
The following stream pointers are available to access the standard streams:
| Pointer | Stream |
|---|---|
stdin | Standard input |
stdout | Standard output |
stderr | Standard error |
These pointers can be used as arguments to functions. Some functions, such as getchar and putchar, use stdin and stdout automatically.
These pointers are constants, and cannot be assigned new values. The freopen function can be used to redirect the streams to disk files or to other devices. The operating system allows you to redirect a program's standard input and output at the command level.
See also
C Send Output To Dev Tty Number
Stream I/O
Global Constants