At some point in time the CoreCLR supported async main entry points. See http://blog.stephencleary.com/2015/03/async-console-apps-on-net-coreclr.html
However both the following programs are not working in .NET Core RTM
using System;
using System.Threading.Tasks;
namespace ConsoleApplication
{
public class Program
{
public static async Task Main(string[] args)
{
await Task.Delay(1000);
Console.WriteLine("Hello World!");
}
}
}
or
using System;
using System.Threading.Tasks;
namespace ConsoleApplication
{
public class Program
{
public async Task Main(string[] args)
{
await Task.Delay(1000);
Console.WriteLine("Hello World!");
}
}
}
These both fail with the error:
error CS5001: Program does not contain a static 'Main' method suitable for an entry point
Are async console applications supported in .NET Core RTM?
Yes, the async Main
functions are supported since .NET Core 2.0
.
dotnet --info
.NET Command Line Tools (2.0.0)
Product Information:
Version: 2.0.0
Commit SHA-1 hash: cdcd1928c9
Runtime Environment:
OS Name: ubuntu
OS Version: 16.04
OS Platform: Linux
RID: ubuntu.16.04-x64
Base Path: /usr/share/dotnet/sdk/2.0.0/
Microsoft .NET Core Shared Framework Host
Version : 2.0.0
Build : e8b8861ac7faf042c87a5c2f9f2d04c98b69f28d
The support for the async Main
functions is introduced in C# version 7.1. However, this functionality is not available out of the box. To make use of this feature you need explicitly specify the C# version 7.1 in your .csproj
file, either by including
<LangVersion>latest</LangVersion>
or by
<LangVersion>7.1</LangVersion>
For example for the ASP.NET core 2.0 project:
<Project Sdk="Microsoft.NET.Sdk.Web">
<PropertyGroup>
<TargetFramework>netcoreapp2.0</TargetFramework>
<LangVersion>latest</LangVersion>
</PropertyGroup>
<ItemGroup>
<PackageReference Include="Microsoft.AspNetCore.All" Version="2.0.0" />
</ItemGroup>
<ItemGroup>
<DotNetCliToolReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Tools" Version="2.0.0" />
<DotNetCliToolReference Include="Microsoft.EntityFrameworkCore.Tools.DotNet" Version="2.0.0" />
<DotNetCliToolReference Include="Microsoft.DotNet.Watcher.Tools" Version="2.0.0" />
</ItemGroup>
</Project>
where the Main function can be rewritten as following:
using System.Threading.Tasks;
...
public static async Task Main(string[] args)
{
await BuildWebHost(args).RunAsync();
}
...
References: