> For the complete documentation index, see [llms.txt](https://www.pinvoke.dev/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://www.pinvoke.dev/kernel32/virtualprotect.md).

# VirtualProtect

```csharp
[DllImport("KERNEL32.dll", ExactSpelling = true, SetLastError = true)]
[DefaultDllImportSearchPaths(DllImportSearchPath.System32)]
public static extern unsafe BOOL VirtualProtect(
    void* lpAddress,
    nuint dwSize,
    PAGE_PROTECTION_FLAGS flNewProtect,
    PAGE_PROTECTION_FLAGS* lpflOldProtect);
```

[PAGE\_PROTECTION\_FLAGS](/memory/page_protection_flags.md)