---
description: "Learn more about: noreturn"
title: "noreturn"
ms.date: "11/04/2016"
f1_keywords: ["noreturn_cpp"]
helpviewer_keywords: ["__declspec keyword [C++], noreturn", "noreturn __declspec keyword"]
ms.assetid: 9c6517e5-22d7-4051-9974-3d2200ae4d1d
---
# noreturn

**Microsoft Specific**

This **`__declspec`** attribute tells the compiler that a function does not return. As a consequence, the compiler knows that the code following a call to a **`__declspec(noreturn)`** function is unreachable.

If the compiler finds a function with a control path that does not return a value, it generates a warning (C4715) or error message (C2202). If the control path cannot be reached due to a function that never returns, you can use **`__declspec(noreturn)`** to prevent this warning or error.

> [!NOTE]
> Adding **`__declspec(noreturn)`** to a function that is expected to return can result in undefined behavior.

## Example

In the following sample,the **`else`** clause does not contain a return statement.  Declaring `fatal` as **`__declspec(noreturn)`** avoids an error or warning message.

```cpp
// noreturn2.cpp
__declspec(noreturn) extern void fatal () {}

int main() {
   if(1)
     return 1;
   else if(0)
     return 0;
   else
     fatal();
}
```

**END Microsoft Specific**

## See also

[__declspec](../cpp/declspec.md)<br/>
[Keywords](../cpp/keywords-cpp.md)