Function protect 

pub unsafe fn protect(x: SEXP) -> TlsRoot

Protect a value using the current TLS scope.

Panics

Panics if called outside of a with_protect_scope block.

Safety

• Must be called from the R main thread
• x must be a valid SEXP
• Must be called within a with_protect_scope block

Example

tls::with_protect_scope(|| {
    let x = tls::protect(some_sexp);
    // use x...
})