Function opt_mut

src/backend/linux_raw/conv.rs:224–231

(t: Option<&mut T>)

/// syscall.
#[inline]
pub(super) fn opt_mut<T: Sized, Num: ArgNumber>(t: Option<&mut T>) -> ArgReg<'_, Num> {
    // This optimizes into the equivalent of `transmute(t)`, and has the
    // advantage of not requiring `unsafe`.
    match t {
        Some(t) => by_mut(t),
        None => raw_arg(null_mut()),
    }
}

/// Convert an optional immutable reference into a `usize` for passing to a
/// syscall.