Re: Segmentation fault

[Michael Powell <mwpowellhtx at gmail dot com>]

Below...

On Wed, Mar 6, 2013 at 1:49 PM, Bill Pringlemeir <bpringle@sympatico.ca> wrote:
> On  6 Mar 2013, mwpowellhtx@gmail.com wrote:
>
>> I ran ldd on the x86 build, and I get not a dynamic executable. So I
>> guess meaning there are no shared libraries of any sort. Okay.
>
> Your PC should always return that.  The ldd on the PC is not for 'cross
> development'.
>
>> Then I run <cross/>-ldd --root / <app/>, and it doesn't return
>> anything to me. But I doubt it would because I'm not linking any known
>> libraries to it dynamically.
>
> Do you compile with '-static'?  Then this is not your issue.  Look no
> further.

Bingo. Yessir, it is. I build the (apparently) offensive library as a
static '.a' library and link it in statically.

I happen to be including i2c-dev.h from /usr/include, which may not be
right. I look at the apparent same one from the cross compiler
location, and it is obviously a different version.

Or perhaps this is barking up the tree of populating my cross compiler
with the necessary packages, libraries, and headers?

> Copy the '<cross/>-ldd' to the target.  It is a shell script.  It starts
> with '#!/bin/bash', but you should be able to change to '#!/bin/sh'.  It
> uses some environment variables that 'ld.so' examines for debugging.
> You can type 'man ld.so' on a PC if you are interested... OR forget this
> advice.
>
> You need to have a 'shadow' directory structure setup on the PC to run
> the '<cross/>-ldd' on the PC.
>
> In my experience, it is easy to build a linux kernel than it is to get a
> 'root file system' correct.  There are a lot of concepts to understand.
> Maybe you can try your application with '-static'.  It will be bigger,
> but it will tell you if 'libraries' are your issue.  If a '-static'
> version works but a 'non-static' does not, then you have 'library
> issues'.
>
> hth,
> Bill Pringlemeir.
>
>
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