[Ipopt] Missing random generator function using Cygwin 64

Stefan Vigerske stefan at math.hu-berlin.de
Tue Jun 10 14:17:17 EDT 2014


I'm running GCC 4.9.0 under Linux and get no problem:

checking whether drand48 is declared... yes
checking whether rand is declared... yes
checking whether srand is declared... yes


On 06/10/2014 05:57 PM, Tony Kelman wrote:
> Good.
> 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.
> Thanks,
> Tony
> From: Yao Xie
> Sent: Tuesday, June 10, 2014 8:28 AM
> To: Tony Kelman ; ipopt at list.coin-or.org
> Subject: RE: [Ipopt] Missing random generator function using Cygwin 64
> Yes, it works... after I downgraded gcc from 4.8.3 to 4.8.2
> Thanks again.
> Yao
> --------------------------------------------------------------------------------
> From: Tony Kelman (kelman at berkeley.edu)
> Sent: Tuesday, June 10, 2014 08:49 AM
> To: Yao Xie (xieyao04 at gmail.com); ipopt at list.coin-or.org
> Subject: Re: [Ipopt] Missing random generator function using Cygwin 64
> Ah, crap.
> conftest.cc:75:22: error: ISO C++ forbids casting between pointer-to-function and pointer-to-object [-Werror=pedantic]
>     char *p = (char *) rand;
>                        ^
> 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?
> -Tony
> 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 gist.github.com and send a link in your message.
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