Using open source software in proprietary software
<p>I am developing a program from another program (a fork) under GPLv3. I know that if &quot;my&quot; program is used commercially or just distributed (as opposed to just personal use) it should keep the same license.</p>
<p>I don't understand from the GPLv3 license terms, whether this program which would be available open source, can be used as a piece inside proprietary software or not.</p>
<p>Can someone let me know and maybe tell which part of the license states this?</p>

<p>If proprietary software contains GPL-licensed software then the same rules apply. Whether it's 99% GPL-licensed with 1% changes, or 99% proprietary with 1% GPL-licensed code added, makes no legal difference.</p>

copyright software