Function posish::fs::is_file_read_write

pub fn is_file_read_write<Fd: AsUnsafeHandle>(fd: &Fd) -> Result<(bool, bool)>

fcntl(fd, F_GETFL) & O_ACCMODE. Returns a pair of booleans indicating whether the file descriptor is readable and/or writeable, respectively. This is only reliable on files; for example, it doesn't reflect whether sockets have been shut down; for general I/O handle support, use crate::io::is_read_write.