Type Alias mx_meth 

pub type mx_meth = unsafe extern "C" fn(data: *mut c_void, argc: i32, argv: *const SEXP) -> SEXP;

Method signature for trait vtable entries.

All trait methods are erased to this uniform signature:

• data: Pointer to the concrete object data
• argc: Number of arguments in argv
• argv: Array of SEXP arguments from R
• Returns: SEXP result to R

Argument Handling

The shim generated by #[miniextendr] on a trait is responsible for:

1. Checking argc matches expected arity
2. Converting each argv[i] via TryFromSexp
3. Calling the actual method
4. Converting the result via IntoR
5. Catching panics and converting to R errors

Safety

This function pointer is unsafe because:

• data must point to valid, properly-aligned data of the expected type
• argv must point to argc valid SEXP values, each rooted by the caller for the whole call (the shim’s conversions and the method body allocate); the generated View protects each argument before converting the next
• The returned SEXP is unprotected; the caller roots it before allocating
• Must be called on R’s main thread

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 8 bytes