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Re: apt-build options

Rob Leach wrote on 15/05/2006 18:53:
> I've tried tailoring apt-build (via apt-build.conf) to
> use the Debian standard build options. The output from
> any apt-builds that I do don't seem to indicate that
> any of these options are being picked up at all. Does
> anyone know how I can tell how a binary file was
> compiled? I was hoping that it could have perhaps been
> something as simple as `bash --compiled`, and it would
> tell me it was compiled as i686 or something like
> that. The `file /bin/bash` command does not seem to
> give me what I'm looking for either.

Unless the program itself has some support for this in its respective
build system, so that the optimisation settings used during compilation
are stored (probably as part of the version message) in the binary,
there is no way I know of to reconstruct even parts of those settings
from the binary. It might be possible to deduce the exact processor the
binary was compiled for by analysing which assembler commands are used
in that binary (and guess that a binary containing an assembler command
only available on an i686 is compiled for that processor), but this is
imprecise (mostly because a binary might have different subroutines for
some functions depending in the processor it is executed on).
So, to the best of my knowledge, there is no way of finding out what
optimisations were enabled in the compiler while compiling a specific

As to wether apt-build actually passes its options to the build script
of a specific package, you should probably try and contact the apt-build
maintainer and/or the maintainer of the package you want apt-build to
compile with specific settings. Unfortunately, there are certainly a
number of packages which do not use those options apt-build passes to
them. Some because the maintainers simply don't know the way apt-build
works, some because their package only works reliably with some specific
optimisations turned on (or more likely: off), some because the work
needed for that is simply not justified for the given package.


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