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<DIV>I know where it’s coming from, and it would also go away by upgrading
autotools since this char *p = (char *) rand; method isn’t used in autoconf for
checking the existence of a function any more. The mystery is why something that
was a warning in GCC 4.8.2 (and everywhere else, except I think clang on Linux)
would become an error in GCC 4.8.3 without changing any compiler flags. And
whether that’s a Cygwin-only quirk, or would happen elsewhere. If it happens
elsewhere, then it’s more of an issue and should maybe be reported to GCC as a
regression since we’re not the only project in the world still using old
autotools.</DIV>
<DIV> </DIV>
<DIV>-Tony</DIV>
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<DIV style="font-color: black"><B>From:</B> <A title=ted@Lehigh.EDU
href="mailto:ted@Lehigh.EDU">Ted Ralphs</A> </DIV>
<DIV><B>Sent:</B> Thursday, July 03, 2014 8:49 PM</DIV>
<DIV><B>To:</B> <A title=stefan@math.hu-berlin.de
href="mailto:stefan@math.hu-berlin.de">Stefan Vigerske</A> </DIV>
<DIV><B>Cc:</B> <A title=kelman@berkeley.edu
href="mailto:kelman@berkeley.edu">Tony Kelman</A> ; <A
title=ipopt@list.coin-or.org href="mailto:ipopt@list.coin-or.org">ipopt</A>
</DIV>
<DIV><B>Subject:</B> Re: [Ipopt] Missing random generator function using Cygwin
64</DIV></DIV></DIV>
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<DIV dir=ltr>I've replicated this on the Windows box I have on Jenkins. You can
get all the build logs etc from there:
<DIV> </DIV>
<DIV><A
href="http://jenkins.coin-or.org:8080/job/all-t-dll-x86_64-pc-cygwin-gcc4.8.1/135/console">http://jenkins.coin-or.org:8080/job/all-t-dll-x86_64-pc-cygwin-gcc4.8.1/135/console</A><BR></DIV>
<DIV> </DIV>
<DIV>Upgrading to 4.9.0 should fix the problem, as Stefan indicated, but I'll
leave it on 4.8.3 to try to chase down the problem. Incidentally, I upgraded to
4.8.3 to try to fix what seemed to be a bug in 4.8.1 that was preventing OS from
building.<BR></DIV>
<DIV> </DIV>
<DIV>Cheers,</DIV>
<DIV> </DIV>
<DIV>Ted</DIV>
<DIV> </DIV>
<DIV>Cheers,</DIV>
<DIV> </DIV>
<DIV>Ted</DIV></DIV>
<DIV class=gmail_extra><BR><BR>
<DIV class=gmail_quote>On Tue, Jun 10, 2014 at 2:17 PM, Stefan Vigerske <SPAN
dir=ltr><<A href="mailto:stefan@math.hu-berlin.de"
target=_blank>stefan@math.hu-berlin.de</A>></SPAN> wrote:<BR>
<BLOCKQUOTE class=gmail_quote
style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">Hi,<BR><BR>I'm
running GCC 4.9.0 under Linux and get no problem:<BR><BR>checking whether
drand48 is declared... yes<BR>checking whether rand is declared...
yes<BR>checking whether srand is declared... yes<SPAN class=HOEnZb><FONT
color=#888888><BR><BR>Stefan</FONT></SPAN>
<DIV><BR><BR>On 06/10/2014 05:57 PM, Tony Kelman wrote:<BR></DIV>
<BLOCKQUOTE class=gmail_quote
style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">
<DIV>Good.<BR><BR>This worries me slightly. If anyone on the mailing list
has access to a Linux distribution where GCC 4.8.3 is already easily
available, I’d appreciate if you could contact me and let me know whether or
not you see the same thing. I have no idea at the moment whether this change
in behavior is specific to Cygwin or will start showing up on Linux as
well.<BR><BR>Thanks,<BR>Tony<BR><BR><BR>From: Yao Xie<BR>Sent: Tuesday, June
10, 2014 8:28 AM<BR>To: Tony Kelman ; <A
href="mailto:ipopt@list.coin-or.org"
target=_blank>ipopt@list.coin-or.org</A><BR>Subject: RE: [Ipopt] Missing
random generator function using Cygwin 64<BR><BR>Yes, it works... after I
downgraded gcc from 4.8.3 to 4.8.2<BR><BR>Thanks
again.<BR><BR>Yao<BR><BR></DIV>------------------------------<U></U>------------------------------<U></U>--------------------
<DIV><BR>From: Tony Kelman (<A href="mailto:kelman@berkeley.edu"
target=_blank>kelman@berkeley.edu</A>)<BR>Sent: Tuesday, June 10, 2014 08:49
AM<BR>To: Yao Xie (<A href="mailto:xieyao04@gmail.com"
target=_blank>xieyao04@gmail.com</A>); <A
href="mailto:ipopt@list.coin-or.org"
target=_blank>ipopt@list.coin-or.org</A><BR>Subject: Re: [Ipopt] Missing
random generator function using Cygwin 64<BR>Ah, crap.<BR>conftest.cc:75:22:
error: ISO C++ forbids casting between pointer-to-function and
pointer-to-object [-Werror=pedantic]<BR> char *p = (char
*)
rand;<BR>
^<BR>Apparently you’ve updated your GCC more recently than I have, and now
in 4.8.3 this old-autotools method of checking for the existence of a
function is an error, where it used to be a warning. I’m really surprised
the grouping of a warning would be changed in a point release like that...
the right solution is to update our autotools version, but that’s a big job
that we haven’t put enough full-time work into yet. I’ll try to think if
there’s a quick short-term fix for this, but in the meantime can you try
reverting your GCC version to the previous release through Cygwin’s setup
program?<BR>-Tony<BR>P.S: The attachment came through to me personally, but
I guess not the mailing list. For future use you can try uploading log files
somewhere like <A href="http://gist.github.com"
target=_blank>gist.github.com</A> and send a link in your
message.<BR><BR><BR><BR></DIV>
<DIV>______________________________<U></U>_________________<BR>Ipopt mailing
list<BR><A href="mailto:Ipopt@list.coin-or.org"
target=_blank>Ipopt@list.coin-or.org</A><BR><A
href="http://list.coin-or.org/mailman/listinfo/ipopt"
target=_blank>http://list.coin-or.org/<U></U>mailman/listinfo/ipopt</A><BR><BR></DIV></BLOCKQUOTE>
<DIV class=HOEnZb>
<DIV
class=h5><BR>______________________________<U></U>_________________<BR>Ipopt
mailing list<BR><A href="mailto:Ipopt@list.coin-or.org"
target=_blank>Ipopt@list.coin-or.org</A><BR><A
href="http://list.coin-or.org/mailman/listinfo/ipopt"
target=_blank>http://list.coin-or.org/<U></U>mailman/listinfo/ipopt</A><BR></DIV></DIV></BLOCKQUOTE></DIV><BR><BR
clear=all>
<DIV> </DIV>-- <BR>Dr. Ted Ralphs<BR>Associate Professor, Lehigh
University<BR>(610) 628-1280<BR>ted 'at' lehigh 'dot' edu<BR><A
href="http://coral.ie.lehigh.edu/~ted"
target=_blank>coral.ie.lehigh.edu/~ted</A><BR></DIV></DIV></DIV></DIV></BODY></HTML>