pub unsafe fn fcntl(fd: int, cmd: int, arg: impl AsRawV) -> Result<int>Expand description
Manipulate characteristics of a file descriptor.
This system call is particularly unsafe, because the final argument
gets interpreted in very different ways depending on the value of
the cmd argument. Callers must take care to ensure that arg is of
an appropriate type and value for the selected cmd.
Set arg to () (empty tuple) for commands whose argument is specified
as “void” in the documentation.