License

RCBasic is available under the zlib license.

Full License Text

This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.

Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:

1. The origin of this software must not be misrepresented; you must not
   claim that you wrote the original software. If you use this software
   in a product, an acknowledgment in the product documentation would
   be appreciated but is not required.

2. Altered source versions must be plainly marked as such, and must not
   be misrepresented as being the original software.

3. This notice may not be removed or altered from any source
   distribution.

Summary

In practical terms the zlib license means you can:

• Use RCBasic in commercial projects.

• Modify the source code freely.

• Redistribute modified versions, as long as you mark them as modified and do not claim they are the original.

• Ship your game or application without any mandatory attribution (though a credit is appreciated).