[gnu.misc.discuss] Copylefted Library Functions

jym@APPLE.COM (08/11/89)

I have a few "devil's advocate" questions.

Let's say I write a program that uses termcap functions.  If I'm on a Unix
 system, I have a choice:  I can write my program using the termcap library
  that came with Unix, or I can use the GNU termcap library, whose source is
   among the Emacs source.  GNU termcap has a few extra features, but in this
    example, I don't use them:  I would write the same code no matter which
     termcap library I used.

And let's say it's an unfree program:  you have to pay to get it, nobody can
 see the source, the whole works.  Does that mean I have to *not* use the
  GNU termcap library?

Suppose I'm a big fan of the GNU termcap library, and think it's better than
 the one I got with my Unix.  So much so that with every copy of my unfree
  program that I sell to somebody, I give away the GNU termcap library (with
pp   source and all) and recommend that people use it instead of what they
    might have with their Unix.  (I distribute my unfree program in such a
     way that they can link either library in.)  Can I do that?

Or let's say somebody has unfree programs distributed as object files.
 Can't they, under their own initiative, choose to link in the GNU termcap
  library they happen to already have?  Legally, is there a difference?

And finally, let's say this program also runs on VMS, an operating system
 that doesn't come with a termcap library.  Can I give away copies of the
  GNU termcap library (source and all) to each person I sell the unfree
   program to?  Bear in mind that the program would not work at all without
    a termcap library.  (I don't know if there are other termcap libraries
     that work on VMS.)

And, finally, does the answer to any of these questions change if I do use
 the extra GNU-only features of the GNU termcap library?
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