Module error 

Error handling helpers for R API calls.

Default path: error_in_r (the standard for #[miniextendr])

Every #[miniextendr] function runs inside with_r_unwind_protect_error_in_r. Rust panics and user-raised conditions (error!(), warning!(), message!(), condition!()) are caught, packaged as a tagged SEXP, and returned normally. The generated R wrapper inspects the SEXP and raises the appropriate R condition with rust_* class layering. No Rf_error longjmp happens on this path.

User code should use:

• panic!() — for unrecoverable Rust errors (becomes rust_error in R)
• error!() / warning!() / message!() / condition!() — for structured R conditions (see crate::condition)

When Rf_error fires

Rf_error / Rf_errorcall (longjmp) is only used on three paths where there is no R wrapper to inspect a tagged SEXP:

1. Trait-ABI vtable shims — cross-package C-ABI calls go through with_r_unwind_protect (non-error_in_r).
2. ALTREP RUnwind guard — ALTREP callbacks invoked from R’s GC / vector dispatch use with_r_unwind_protect_sourced.
3. Explicit opt-out — #[miniextendr(no_error_in_r)] / unwrap_in_r.

r_stop (this module) is the internal Rust wrapper around Rf_error. It is used by proc-macro generated argument validation and return-type unwrapping, which run before the closure enters with_r_unwind_protect. User code should never call r_stop directly.

Example

use miniextendr_api::miniextendr;

#[miniextendr]
fn validate_input(x: i32) -> i32 {
    assert!(x >= 0, "x must be non-negative, got {x}");
    x * 2
}

Functions

_r_print_newline 👻

Print a newline to R’s console (internal implementation). Automatically routes to R’s main thread if called from a worker thread.

_r_print_str 👻

Print a message to R’s console (internal implementation). Automatically routes to R’s main thread if called from a worker thread.

r_stop

Raise an R error via Rf_error (longjmp). Do not call from user code.

r_warning

Raise an R warning with the given message.