why is gmcs command in bash(mono) missing the namespace `System.Threading'?

Question

I input this command

gmcs -t:library Program.cs

and get this error

Program.cs(6,14): error CS0234: The type or namespace name `Tasks' does not exist in the namespace `System.Threading'. Are you missing an assembly reference?

I get I have to give it the paths and everything, but how? can't find the way to do it

Answer 1

gmcs targets the .NET 2.0 profile, Task didn't exist back then.

On a recent Mono just use mcs, as gmcs is deprecated and was removed from Mono 4.0.