C - How to communicate (natively) with ttySx?

nathanhi · 11-26-2009, 04:26 AM

Hello,

I just want to write a little piece of software in C to communicate with a "special" device over serial Port. Will I have to use fopen() or are there any better ways to realize this? I want to write and read to/from the serial device. Last but not least a second question: How can I distribute parts of my Code in several files and compile them that I get one Binary? I'm currently writing functions into an header file, is this the right way?

Greetings,
Nathan

P.S.: I know, my English is bad. Sorry.

theNbomr · 11-26-2009, 09:15 AM

In Linux, devices (like serial ports), are abstracted as files. To use them, you use the same paradigm as used for accessing files: open(), read() write(), close(), etc. For serial ports, you also use the termios interface to set parameters such as bit rate, word size, parity, and especially terminal oriented processing performed by the device driver, such as end-of-line processing.
For more good information on serial port programming, and useful sample code:
Serial HOWTO
Serial Programming HOWTO
Serial Programming Guide for POSIX Operating Systems

As a general rule, you can compile individual source files to object code, and then link them into a single runtime binary executable.

Code:

gcc -o module1.o -c module1.c
gcc -o module2.o -c module2.c
gcc -o module3.o -c module3.c
ld -o mainmodule module1.o module2.o module3.o

gcc can perfom the linkage phase, as well. There are many many options that can be applied, many of which are normally required, such as supplying directives to allow the compiler and linker to locate header files and libraries. See the gcc man page for a start.

Your use of English puts many native English writers to shame. No apologies required.

--- rod.

nathanhi · 11-27-2009, 08:11 AM

Quote:

Originally Posted by theNbomr

In Linux, devices (like serial ports), are abstracted as files. To use them, you use the same paradigm as used for accessing files: open(), read() write(), close(), etc. For serial ports, you also use the termios interface to set parameters such as bit rate, word size, parity, and especially terminal oriented processing performed by the device driver, such as end-of-line processing.
For more good information on serial port programming, and useful sample code:
Serial HOWTO
Serial Programming HOWTO
Serial Programming Guide for POSIX Operating Systems

As a general rule, you can compile individual source files to object code, and then link them into a single runtime binary executable.

Code:

gcc -o module1.o -c module1.c
gcc -o module2.o -c module2.c
gcc -o module3.o -c module3.c
ld -o mainmodule module1.o module2.o module3.o

gcc can perfom the linkage phase, as well. There are many many options that can be applied, many of which are normally required, such as supplying directives to allow the compiler and linker to locate header files and libraries. See the gcc man page for a start.

Your use of English puts many native English writers to shame. No apologies required.

--- rod.

Hi,

thank you! You made my day.

Greetings,
Nathan