Include C# Is It Possible To Include Something Only If Something Else Is Included In C++?

Is it possible to include something only if something else is included in C++? - include c#

I write in C + + header file for both allegro and console programs. But I will do "colours.h" only if \\ \\ \\ \\ \\ \\ \\ \\ u0026lt; allegro.h> recorded included.

Is there a command that they are "colours.h" only if \\ \\ \\ \\ \\ \\ \\ \\ u0026lt;> Date allegro.h will say?