---
description: "Learn more about: Warning C26448 USE_GSL_FINALLY"
title: Warning C26448
ms.date: 03/22/2018
f1_keywords: ["C26448", "USE_GSL_FINALLY"]
helpviewer_keywords: ["C26448"]
---
# Warning C26448

> Consider using `gsl::finally` if final action is intended (gsl.util)

C++ Core Guidelines: [GSL.util: Utilities](https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#SS-utilities)

The Guidelines Support Library provides a convenient utility to implement the *final action* concept. Since the C++ language doesn't support **try-finally** constructs, it became common to implement custom cleanup types that would invoke arbitrary actions on destruction. The `gsl::finally` utility is implemented in this way and provides a more uniform way to perform final actions across a code base.

There are also cases where final actions are performed in an old-fashioned C-style way by using **`goto`** statements (which is discouraged by [C26438 NO_GOTO](c26438.md)). It's hard to detect the exact intention in code that heavily uses **`goto`**, but some heuristics can help to find better candidates for cleanup.

## Remarks

- This rule is lightweight and uses label names to guess about opportunities to use final action objects.
- Label names that can raise a warning contain words like "end", "final", "clean", and so on.
- Warnings appear at the **`goto`** statements. You may see verbose output on some occasions, but the output may help in prioritizing code, depending on its complexity.
- This rule always goes in pair with [C26438 NO_GOTO](c26438.md). Depending on the priorities, one of these rules can be disabled.

Code analysis name: `USE_GSL_FINALLY`

## Example

Cleanup with multiple goto statements:

```cpp
void poll(connection_info info)
{
    connection c = {};
    if (!c.open(info))
        return;

    while (c.wait())
    {
        connection::header h{};
        connection::signature s{};
        if (!c.read_header(h))
            goto end;               // C26448 and C26438
        if (!c.read_signature(s))
            goto end;               // C26448 and C26438
        // ...
    }

end:
    c.close();
}
```

Cleanup with multiple goto statements replaced by `gsl::finally`:

```cpp
void poll(connection_info info)
{
    connection c = {};
    if (!c.open(info))
        return;

    auto end = gsl::finally([&c] { c.close(); });
    while (c.wait())
    {
        connection::header h{};
        connection::signature s{};
        if (!c.read_header(h))
            return;
        if (!c.read_signature(s))
            return;
        // ...
    }
}
```