[Bug c++/45249] Indirect variable parameters sometimes cause segmentation fault

["rogerio at rilhas dot com" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #18 from rogerio at rilhas dot com  2010-08-11 13:11 -------
Of course vsnprintf was my first choice, as you can see from the WIN32 part of
the code I sent you. In WIN32 I can use vsnprint in a very natural and
predictable way in "format_indirect". In LINUX this cannot be used in
"format_indirect" as GCC does not allow me to use vsnprintf on a function that
doesn't take variable parameters. I tried to bypass it specifying variable
parameters for "format_indirect", but of course the results are wrong because
GCC will have placed the wrong address in "format_address" inside
"format_indirect". So, in fact, vsnprintf will have exactly the same problem as
I had, and I would report exactly the same bug like I did.

As you can see I've tried very hard to explain all details of the problem, and 
why this is a bug in GCC.

You just keep dismissing all my arguments without any justification whatsoever.
When you did justify I just proved your arguments to be false (no disrespect
intended) in the hope that this conversation would progress.

You don't explain why I can't rely on the calling convention to ensure the
parameters will be adjacent, and you don't explain why I can't use &format to
get the address of that packed data on the stack. You just keep invoking some
standard where these 2 things are alledgedly not defined but without
materializing it (which I don't believe you can anyway!). You have not yet
shown why GCC is not required to place the parameters correctly on the stack,
and why GCC does not need to give me the true &format.

So I'm stuck with your "you can't because you can't" replies and this
conversation will not progress any further, of course.

Best regards,
Rogerio


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45249