The question of “can I use an Open Source application, or just a piece of one, in my closed source / proprietary application” has been a one sided debate for several years. Those who have actually read the various GPL versions, read compatible licenses (such as the MIT and Creative Commons licences), understand clearly the spirit and intent of these works. Those who haven’t, often are appalled and even offended when they are first brought up to speed on what the answer really is.
So, let’s take a look…
The Free Software Foundation (contributors to the authoring of modern GPL licenses) states:
“[P]eople have been wondering what the rules are when you link to some GPLv3-covered code. They’re the same as they were under GPLv2: the combined work you create needs to be GPLed as well.”
What is “linking”, or what does it mean to “link to” covered code. Linking is the direct use of, inclusion by means of programmatic call (such as a php ‘include’ or ‘require’ statement) , or any like means of integration.
This is the answer to the age old argument, “the original work was Open Source, but our implementation of that – to make it a working system – is not”. Clearly, that is a false argument. An implementation is, by definition, a linking. The combined work must be GPL’d in one form or another, or issued and made available under a compatible license.
Here’s the word of ‘God’… Richard Stallman – he founded the GNU Project in 1984. He is the principal or initial author of GNU Emacs, the GNU C Compiler, the GNU Debugger GDB and parts of other packages. He is the President of the Free Software Foundation (FSF).
“I once found out about a non-free program which was designed to use Readline [a library covered by GPL], and told the developer this was not allowed. He could have taken command-line editing out of the program, but what he actually did was rerelease it under the GPL.”
Reference – http://www.gnu.org/philosophy/pragmatic.html
This represents public precedence. Stallman effectively enforced his right as the author or co-author of a piece of GPL licensed software, and the offending party conceded the point by releasing the entire new work under the GPL.
Lastly, the modern GNU states, directly:
“You cannot incorporate GPL-covered software in a proprietary system…. A system incorporating a GPL-covered program is an extended version of that program…. [and] must be released under the GPL.”
This has been explained in detail, to the extent that using GPL-covered code in so much as a plugin of a massive proprietary system, now makes the entire proprietary system GPL-covered.
Why bother using anything GPL-covered then? Doesn’t it weaken your financial foothold in the software industry? Doesn’t it take away your opportunities?
Quite the opposite.
GPL-covered code makes your financial foothold stronger by creating more and more opportunities for growth and profit. The modern software model is one of labor and support, not product. For years, consumers have asked for easy-to-use, robust software. Out of fear of competition, and in an attempt to lock customers into a single solution, proprietary code was create in such a manner as to not allow anyone else to understand the inner workings of existing systems. An Open Source software author’s single goal is to provide robust solutions – and by satisfying the customer’s original need, they inherently build trust and loyalty, bringing the customer back again and again. Profit is generated by support, and by project. When the customer desires new functionality, or different solutions, they will come to their trusted software provider for these things, generating cash flow and happiness for both parties.
GPL-covered code also opens the door for new opportunities. Using existing, known working, and well supported GPL-covered code for your projects eliminates the need to duplicate work. Software providers and authors can now generate projects for clients much more quickly in the past, and with greater confidence. A faster turn around time results in a faster return on investment for your clients, which will make them far more likely to choose your firm for their software needs!