On 2023-12-12 14:05, Paul Eggert wrote:
> On 12/12/23 06:36, Sergey Kosukhin wrote:
[...]
>> 2. Some of the macros are refactored versions of the Autoconf macros (NOT
>> the
>> Autoconf Archive macros). For example, I copied AC_FC_LINE_LENGTH from
>> fortran.m4 to a separate file, renamed the macro to ACX_FC_LINE_LENGTH,
>> fixed a
>> couple of issues and refactored it. As far as I understand, I must copy the
>> whole license header from fortran.m4 to my file. There are three things
>> that I
>> am not sure about:
>> a) may I omit the first two lines saying that "This file is part of
>> Autoconf..." because they look a bit misleading in this context?
>> b) may I add an extra copyright line?
>> c) do I have to provide any extra information in the file?
>
> The answers to (a) and (b) are "yes". For (c) it's "no". However, you must
> redistribute a copy of the GPL itself (the "COPYING" file in Autoconf)
> though of course this is not in the .m4 file itself.
I want to add that when distributing ("conveying") any modified versions,
section 5 of the GNU GPL version 3 requires that the work "carry
prominent notices stating that you modified it, and giving a relevant
date." Previous versions of the GPL have a very similar requirement.
There are probably many ways to achieve this but for a single file
it seems to me that the most straightforward way is to add another
notice near the license notice stating that the file was modified
from its original version by whomever on whatever date. I suggest
also including a brief summary of important differences but this
goes beyond the minimum requirements of the GPL.
Cheers,
Nick
