Struct UPtr

Source

pub struct UPtr<T: ?Sized>(/* private fields */);

Expand description

A pointer from LabVIEW for the data.

In general, these should be avoided in favor of UHandle which allows for more functionality such as resizing types.

Implementations§

Source §

impl<T: ?Sized> UPtr<T>

Source

pub fn new(ptr: *mut T) -> Self

Create a new UPtr from a raw pointer

Source

pub unsafe fn as_ref(&self) -> Result<&T>

Get a reference to the internal type. Errors if the pointer is null.

§Safety

This is a wrapper around pointer::as_ref and so must follow its safety rules. Namely:

When calling this method, you have to ensure that either the pointer is null or all of the following is true:
The pointer must be properly aligned.
It must be “dereferenceable” in the sense defined in [the module documentation].
The pointer must point to an initialized instance of T.
You must enforce Rust’s aliasing rules, since the returned lifetime ’a is arbitrarily chosen and does not necessarily reflect the actual lifetime of the data. In particular, while this reference exists, the memory the pointer points to must not get mutated (except inside UnsafeCell).

Source

pub unsafe fn as_ref_mut(&self) -> Result<&mut T>

Get a mutable reference to the internal type. Errors if pointer contains a null.

§Safety

This method wraps the pointer::as_mut method and so follows its safety rules which require all of the following is true:

The pointer must be properly aligned.
It must be “dereferenceable” in the sense defined in the module documentation.
The pointer must point to an initialized instance of T.
You must enforce Rust’s aliasing rules, since the returned lifetime ’a is arbitrarily chosen and does not necessarily reflect the actual lifetime of the data. In particular, while this reference exists, the memory the pointer points to must not get accessed (read or written) through any other pointer.

Source §

impl UPtr<ErrorCluster<'_>>

Source

pub fn wrap_function<R, E: ToLvError, F: FnOnce() -> Result<R, E>>( &mut self, return_on_error: R, function: F, ) -> R

Wrap the provided function in error handling to match LabVIEW semantics.

i.e. no execution on error in, convert return errors into error cluster.

§Parameters

return_on_error - The value to return if an error.
function - The function to wrap. This is intended to be a closure for easy use.

§Example

use labview_interop::types::ErrorClusterPtr;
use labview_interop::errors::LVInteropError;
use labview_interop::types::LStrHandle;

#[no_mangle]
pub extern "C" fn example_function(mut error_cluster: ErrorClusterPtr, mut string_input: LStrHandle) -> i32 {
  error_cluster.wrap_function(42, || -> Result<i32, LVInteropError> {
   // Do some work
   string_input.set_str("Hello World")?;
  Ok(42)
 })
}

Source

pub fn wrap_return_status<E: ToLvError, F: FnOnce() -> Result<(), E>>( &mut self, function: F, ) -> LVStatusCode

Wrap the provided function in error handling to match LabVIEW semantics.

i.e. no execution on error in, convert return errors into error cluster.

This version returns the LabVIEW status code of the error. To return a different value, see ErrorClusterPtr::wrap_function.

§Parameters

function - The function to wrap. This is intended to be a closure for easy use.

§Example

use labview_interop::types::{ErrorClusterPtr, LVStatusCode};
use labview_interop::errors::LVInteropError;
use labview_interop::types::LStrHandle;

#[no_mangle]
pub extern "C" fn example_function(mut error_cluster: ErrorClusterPtr, mut string_input: LStrHandle) -> LVStatusCode {
  error_cluster.wrap_return_status(|| -> Result<(), LVInteropError> {
   // Do some work
   string_input.set_str("Hello World")?;
    Ok(())

 })
}