Function fcntl::fcntl

pub fn fcntl<'a, RF>(
    fd: &'a RF, 
    cmd: FcntlCmd, 
    arg: FcntlArg
) -> Result<FcntlArg, FcntlError> where
    RF: AsRawFd, 

Calls fcntl with the given cmd and arg. On success, the structure passed to the arg parameter is returned as returned by the kernel. Note: Where possible convenience wrappers (such as is_file_locked, lock_file, etc.) should be used as they correctly interpret possible return values of the syscall.

Currently supported cmds:

• FcntlCmd::GetLock
• FcntlCmd::SetLock

Errors

In case of an error (syscall returned an error, invalid arg provided, cmd not supported, etc.) an appropriate value is returned.