[matheusmoreira]

You're right. The manual contains this ominous notice at the very end of the errors section:

https://man7.org/linux/man-pages/man2/write.2.html

> Other errors may occur, depending on the object connected to fd.

I don't understand why every possible result isn't explicitly documented. This is the Linux system call interface, we need to know everything that could happen when we make these calls.

[dfox]

The right assumption is that every syscall can return any defined errno value. In practice this means that you should handle the cases that you have to handle (-EINTR and for write(2) incomplete writes, which are typical reason for “fatal error: Success”), that you can somehow handle (things like retries for -ENOSPC) and log strerror(3) result for anything that you don't expect (whether you shoult then abort(), exit() or continue depends on how critical the failed syscall was).