Why do I get the error “Unsafe code may only appear if compiling with /unsafe”?

147
votes

Why do I get the following error?

Unsafe code may only appear if compiling with /unsafe"?

I work in C# and Visual Studio 2008 for programming on Windows CE.

6
c#visual-studio-2008windows-ceunsafe
See msdn.microsoft.com/en-us/library/ezb5hwx9%28VS.80%29.aspx and msdn.microsoft.com/en-us/library/t2yzs44b%28VS.80%29.aspx - Dirk Vollmar
Possible duplicate of I can seem to get msbuild to build unsafe code blocks - stack247

6 Answers

283
votes

To use unsafe code blocks, the project has to be compiled with the /unsafe switch on.

Open the properties for the project, go to the Build tab and check the Allow unsafe code checkbox.

133
votes

Here is a screenshot:

Unsafe screenshot

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4
votes

Probably because you're using unsafe code.

Are you doing something with pointers or unmanaged assemblies somewhere?

4
votes

Search your code for unsafe blocks or statements. These are only valid is compiled with /unsafe.

4
votes

To use unsafe code blocks, open the properties for the project, go to the Build tab and check the Allow unsafe code checkbox, then compile and run.

class myclass
{
     public static void Main(string[] args)
     {
         unsafe
         {
             int iData = 10;
             int* pData = &iData;
             Console.WriteLine("Data is " + iData);
             Console.WriteLine("Address is " + (int)pData);
         }
     }
}

Output:

Data is 10
Address is 1831848
3
votes

For everybody who uses Rider you have to select your project>Right Click>Properties>Configurations Then select Debug and Release and check "Allow unsafe code" for both.Screenshot