[yawboakye]

every program is given the 3 stdio channels: stdin, stdout, stderr. if the program is unable to use any of these as expected, it's an error that should be reported back to the user. today it's /dev/full but tomorrow it could be a log file with wrong access perms. you don't want to be returning 2 weeks later to find out that nothing was written, and your program didn't complain.

[secondcoming]

Agreed, the log file example is quite good, but also something like a systemd script reporting success when it actually failed.

[ChrisSD]

This is true of *nix but on Windows they can be absent. In face this is the default for GUI applications.