Re: cross-compiling alternatives (was Re: [PATCH 0/1] Embedded Maintainer(s)...)

[Rob Landley <rob@landley.net>]

On Friday 13 June 2008 04:06:18 Alexander Neundorf wrote:
> > And the above are not really a big problem -
>
> "checking if something builds" is no problem, this just works. Running
> something is a problem, as in "it doesn't just work" (...because you cannot
> run it).

Noticing 2 weeks after deployment that signal handling in the mips version of 
perl is using the x86 signal numbers and they're not the same: priceless.

> > The only simple solution so far (without diving into the implementation
> > and searching for root causes) were AFAICS:
> > - do not use libtool for linking (as the link line as such without
> >   libtool works as expected)
>
> Yes, libtool sucks, it's the wrong solution to the problem.
> (and CMake doesn't use it).

Nothing on Linux really _uses_ libtool.  It's supposed to act as a NOP wrapper 
around the linker on any Linux target.  (It's there for things like Sparc and 
HPUX).

The fact that libtool manages to do its nothing _wrong_ so often would be 
hilarious if it wasn't such a pain.  Just uninstall libtool before trying to 
build for a Linux target, this should never cause any problems and will save 
you lots of headaches.

> > Why on earth does someone need this explicitly during the build?
> > If you have portable software, all of that should be hidden in the code
> > and use "sizeof(int)".

According to the LP64 standard which pretty much all modern Unixes adhere to 
(including both Linux and MacOS X) sizeof(int) is always 4.  Guaranteed.

The LP64 standard:
  http://www.unix.org/whitepapers/64bit.html

The LP64 rationale:
  http://www.unix.org/version2/whatsnew/lp64_wp.html

The insane legacy reasons windows doesn't do this, but in fact sizeof(int) 
will still be 4 there anyway:
  http://blogs.msdn.com/oldnewthing/archive/2005/01/31/363790.aspx

Just FYI. :)

> But this was not the point. My point was: testing something by running an
> executable can be _a lot_ easier than testing the same without running
> something.

I think building natively under qemu is the easy way, yes. :)

> Alex
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-- 
"One of my most productive days was throwing away 1000 lines of code."
  - Ken Thompson.