C tty read write and think

You can open them with the standard file-opening tools of your language and read or write from them. They have some special behaviour that's different to "ordinary" files, but the basics are the same. I'll cover some of the special cases at the end, but first, an experiment. One interesting thing you can do straight from a regular terminal.

C tty read write and think

The code you posted contains no error-recovery at all. It's a bit off-topic on this site to ask how to implement a new feature error-recovery ; but I'll try. It's not clear what your communication protocol looks like. A continuous stream of bytes, to be split into packets of 10 byte packets, with a measurable delay between packets, no reply expected byte packets, after which silence until there is a reply, perhaps with a retry if there no reply I'll assume it isn't 1.

c tty read write and think

So I'll assume that it's 2. In either case, what's important is: There are 10 bytes received probably received quickly with little or no delay between bytes There is then a delay no bytes received after those 10 bytes. Setting Read Timeouts looks interesting.

It may be your best algorithm: However that may have a problem: However, the timeout only applies to the first character read, so if for some reason the driver misses one character inside the N byte packet then the read call could block forever waiting for additional input characters.

You don't say why you want error-recovery after losing a character: Or remove the error byte If you do this then you must be able to recover from getting 9 bytes sometimes. The data I receive should be always 10 bytes in length but I want to be sure that, if there is any error more or less bytes receivedreading will clear buffer before the next data arrive, so that there is always proper data in the buffer to be processed.

It depends on the read mode e. Immediately after you read, there may be more bytes in the driver: Whether you can clear the buffer "before the next data arrive" is difficult to say: I don't know when the next data is supposed to arrive.

Depending on how you handle parity errors, maybe bytes are never lost. If bytes are sometimes lost then you may want to implement logic like: As well as handling too few bytes aboveyou could modify the above to check for receiving more than 10 bytes: If there are extra bytes, then read them all before returning to the 'waiting-for-nextbytes' state otherwise, these extra bytes will mess up your next byte packet.

I think there's an obvious bug in the code. If you read too much data, don't discard the extra bytes:I have to make a simple app for school.

c tty read write and think

I have to write arguments one per line on the terminal, and return on stdout the user choices. For example, I write cat my_app main.c main.h, if the user c. I am a little bit confused about reading and writing to a serial port.

I have a USB device in Linux that uses the FTDI USB serial device converter driver. It’s easy, you always use the communications (by wire or wireless) as if you were using a file, open, read, write, close commands.

You should set the proper COM (Win) tty (Linux) port and the baud rate. ReadWriteThink is a gift for language arts teachers, and it just keeps on giving. There's simply a wealth of high-quality and accessible content here.

It's a particularly great resource if . Linux kernel source tree. Contribute to torvalds/linux development by creating an account on GitHub. I want to write data to a serial port in C++ (linux) for a a Propeller board.

Program works fine when taking input from the console, but when I write strings to it always return: ERROR - .

The TTY demystified