Questions about using code published under the GNU General Public License, version 2

Question

Licenses for software and other works

For my project, I took this code: which is published under the following license: www.gnu.org/licenses/gpl-2.0.html The result of using this code is an executable module, which, in theory, should also be distributed under the GPL V2 license. There are no problems with this - there seems to be nothing to hide, but I would like to clarify about the use of libc and header files. As closely as I read the GPL v2 license, it doesn't say that the resulting code should only link to GPL libraries. For this, they came up with the GPL v3, which prohibits the use of commercial libraries. Correctly? The second question concerns header files. Actually, how can GPL v2 prevent commercial .h files from being used in an open source program?

* FreeDOS32 Floppy Driver *
* by Salvo Isaja *
* *
* Copyright © 2003-2005, Salvatore Isaja *
* *
* This is "fdc.c" - Portable code for Floppy Disk Controller support *
* *
* This file is part of the FreeDOS32 Floppy Driver. *
* *
* The FreeDOS32 Floppy Driver is free software; you can redistribute *
* it and/or modify it under the terms of the GNU General Public License *
* as published by the Free Software Foundation; either version 2 of the *
* License, or (at your option) any later version. *
* *
* The FreeDOS32 Floppy Driver is distributed in the hope that it will *
* be useful, but WITHOUT ANY WARRANTY; without even the implied warranty *
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with the FreeDOS32 Floppy Driver; see the file COPYING.txt; *
* if not, write to the Free Software Foundation, Inc., *
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA *
* *
* ACKNLOWLEDGEMENT *
* This file is derived from fdc.c, floppy controller handler functions *
* Copyright © 1998 Fabian Nunez *
* You can download the original library from Cottontail OS Development *
* Library <www.0xfi.com/oslib/topx.html>, the file is FDC.ZIP *
* The author can be reached by email at: [email protected] *
* or by airmail at: Fabian Nunez *
* 10 Eastbrooke *
* Highstead Road *
* Rondebosch 7700 *
* South Africa *
* Floppy formats and drive parameters table are from the Linux driver *
* linux/kernel/floppy.c *
* Copyright © 1991, 1992 Linus Torvalds *
* Copyright © 1993, 1994 Alain Knaff *


Answer 1

The GPL implies that if you use components licensed under the GPL, then the entire program must be licensed in the same way. If the license agreement for .h says that they cannot be shown to anyone, then in my opinion it is impossible (without violating one of the agreements).