[openssl-dev] [openssl.org #4422] OS X 32-bit PowerPC: blake2b.c:27: warning: integer constant is too large for 'unsigned long' type

Andy Polyakov via RT rt at openssl.org
Mon Mar 14 16:12:58 UTC 2016

> It looks like the ULL suffix should be safe today;

This is misleading statement. *Today* U suffix should be safe, because
standard specifies that compiler should pick type automatically
depending on value of the constant. In order words suffices beyond U are
required only if you need constant to be of wider type, wider than its
value, e.g. 13ULL. Well, even then it might be superfluous, because type
promotion rules might do it for you. Going back to beginning, to "today
U suffix should be safe". Thing is that we kind of live between today
and yesterday, making it work not only with contemporary platforms, but
even older ones. So real question is if there is compiler supporting
64-bit integer (which is OpenSSL minimum requirement) which would
*truncate* constants in question, i.e. with U alone? I'm not aware of
any. Next question is if there is compiler that would *fail* to parse
ULL? Yes, older Microsoft 32-bit compilers would. Do you see where is it
going? It's going toward leaving U alone.

One can wonder if warning is actually justified. I'd argue that this
would be a trick question. Compiler in question obviously accepts long
long, but it's an *extension* to c89 [which we require and rely on]. Now
if compiler already accepts extensions, why would it have to complain
about extended constant values? I mean you either process extensions and
don't complain, or reject extension and complain. Anyway, the U is here
to stay. If warnings sting the eye that much, then the only appropriate
action would be to bump standard compliance by passing -std=c9x as
additional argument to config/Configure. One can argue that it should be
in Configuration/10-main.conf, or be automatically added by ./config.
Yes, I suppose it's appropriate assuming that compilers shipped with
MacOS X all recognize the option.

Ticket here: http://rt.openssl.org/Ticket/Display.html?id=4422
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