OpenSSL compile flags

Iain Morgan imorgan at
Wed Jan 4 04:50:46 EST 2006

Perhaps you meant to send this to one of the OpenSSL mailing lists _not_

On Tue Jan  3 08:19:27 2006, Ryan B. Lynch wrote:
> When building OpenSSL version 0.9.7i (and all prior versions that I've 
> seen) on Linux, the compiler flags passed to 'gcc' include:
>     "-O3 -fomit-frame-pointer -mcpu=pentium"
> This occurs even when the output of `uname -m` and `arch` are "i486".  I 
> have a few machines with hacked 'uname' and 'arch' commands that will 
> report "i486" even when the real arch is "i686", for use in compiling 
> binaries for other i486 systems.  Looking at the 'config' and 
> 'Configure' scripts, it appears that the arch value is guessed based on 
> 'uname', 'arch', and 'cat /proc/cpuinfo', in different cases.  I guess 
> I'm running into a situation where the configure script is looking at 
> "/proc/cpuinfo", which I can't do a quick-and-easy hack to give false data.
> Is there an option that I'm missing to pass a particular arch value to 
> compile OpenSSL for?  Right now, I'm working around this by 'sed'ing the 
> above-mentioned string out of the CCFLAGS variable in the Makefile and 
> replacing it with "-O2 -march=i586 -pipe".  Is this not proper, or 
> should it work OK?  (It seems to work fine, in running it, but there's a 
> lot of things I wouldn't know about it.)
> Also, as a side-note, most of the literature I've seen regarding 'gcc' 
> says that the "-mcpu=" flag is deprecated, and that "-march=" should be 
> used instead.  Is there a reason why OpenSSL uses "-mcpu="?
> Thanks for the time and help, here--OpenSSL and OpenSSH are wonderful 
> tools, and I appreciate all of the effort that goes into them.
> Thanks,
> Ryan
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Iain Morgan

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