exit codes
 

most programs exit 0 on success and non 0 on failure . what if we have some sort of server wich is password protected . on every new connection , a child process is spawned . the child process asks for a password and gets an incorrect one . after this , it will shutdown the socket and exit . question is .. should it exit 0 or non 0 ? is a bad password considered "failure" or not ? wich cases are considered program failures ?

Thats more like a personal decision, if you need to say someway that the password was wrong you could make an exit(EXIT_FAILURE); (i think thats the name of the constant) , if the succed of the program dependes on a succesfull logon, you can consider that if it fails, the program fails too, cuz it couldent fullfill it's objective.

I hope i was in some way helfull for you, Dam.

There is a convention that is defined for error return codes.
They are defined in sysexits.h For example bad user data like a password that you want to exit with error is
see:
http://www.tmk.com/ftp/multinet-cont...ude/sysexits.h