Function pio_package_set_operating_points 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn pio_package_set_operating_points(
    pkg: *mut PioPackage,
    json: *const c_char,
    errbuf: *mut c_char,
    errlen: usize,
) -> i32

Replace the package’s operating point series from json. null or an empty series clears it. Validation is recomputed before this function returns. Returns 0 on success and -1 on error.

This rewrites the handle, so it takes it non-const and needs exclusive access: no other call may touch the same handle concurrently. See pio_package_validate, the other such entry point.