Re: [igraph] Re: shared library error

[Gábor Csárdi]

Hi,

On Wed, Jan 26, 2011 at 12:20 PM, sergiu netotea
<address@hidden> wrote:
> The program crashes in the first few lines:
> #include <igraph.h>
> #include <stdio.h>
> #include <string.h>
> #include <stdlib.h>
> int main()
> {
>    long int ng1 = NG1, ng2 = NG2;
>    unsigned char *seq;
>        //typedef unsigned char byte;
>        printf("%d",sizeof(unsigned char));
> }

This program does not even compile, since NG1 and NG2 are not defined.

> It never reaches that printf output
> the debug message is:
> (gdb) run
> Starting program: /home/netotea/calgn/grna
> warning: no loadable sections found in added symbol-file
> system-supplied DSO at 0x2aaaaaaab000
>
> Program received signal SIGSEGV, Segmentation fault.
> 0x00000039a2468f31 in getc () from /lib64/libc.so.6
>
> I repeat, on cygwin it all runs fine. I reckon it has to do with the
> unsigned char, since it dumps at getc().

I don't see any getc() in your program.

> In my program I have a huge
> table of zeros and ones, NG1xNG2 = 13000x22000, which I store as
> unsigned chars to occupy less space.

Don't allocate large objects on the stack, allocate them in the heap,
with malloc/calloc.

Btw. sizeof() does not return int, so the %d format specification is wrong.

Gabor

> Any ideas? Of course, this is not igraph related anymore..
> S.
>
> On Wed, Jan 26, 2011 at 11:50 AM, Tamas Nepusz <address@hidden> wrote:
>> Dear Sergiu,
>>
>> LD_LIBRARY_PATH is definitely a good step towards the solution; it seems
>> like your system does not look for shared libraries in /usr/local/lib by
>> default, and that's where you put the igraph libs. You can force your
>> system to look for libs there either by setting LD_LIBRARY_PATH (I'd do
>> it in the shell profile if I were you so that it is enforced every time
>> you log in), or by adding /usr/local/lib to /etc/ld.so.conf.
>>
>> As for the segmentation fault, we need more information to sort that
>> out; at least we have to know which function the program crashes in.
>> First, try to compile your program using the -g switch to add the debug
>> symbols to the executable, then run it under gdb (the GNU debugger) and
>> list the backtrace (using the "bt" command) when it crashes. The
>> backtrace is invaluable to determine whether the crash happens somewhere
>> in igraph or not. (And if it does, we would also need the source code of
>> your program, or even better, a self-contained example that reproduces
>> the crash).
>>
>> --
>> Tamas
>>
>>> Some further news,
>>> I checked the content of $LD_LIBRARY_PATH and it was empty, so I added my 
>>> path:
>>> export LD_LIBRARY_PATH=/usr/local/lib:$LD_LIBRARY_PATH
>>>
>>> Now my program ran but with a segmentation fault. However I got no seg
>>> faults on cygwin :((
>>> Not sure that I solved the shared library problem though, make it
>>> chooses the wrong file, I saw three:
>>> libigraph.so libigraph.so.0  libigraph.so.0.0.0
>>>
>>>
>>>
>>> On Wed, Jan 26, 2011 at 11:03 AM, sergiu netotea
>>> <address@hidden> wrote:
>>>> Hi,
>>>>
>>>> I have a server running Red Hat Enterprize edition, I installed the
>>>> igraph library from source code following the normal ./configure,
>>>> make, make install steps. I have a program that runs well on my local
>>>> cygwin, compiled with:
>>>> gcc grn.c -Wall -I/usr/local/include/igraph -L/usr/local/lib -ligraph -o 
>>>> grna
>>>>
>>>> It does compile on the server without any message but when I run it, it 
>>>> gives:
>>>> ./grna: error while loading shared libraries: libigraph.so.0: cannot
>>>> open shared object file: No such file or directory
>>>>
>>>> However the libs are there, beside the fact that in the compilation
>>>> step it managed to find them:
>>>> ls /usr/local/lib
>>>> libgsl.a  libgslcblas.a  libgslcblas.la  libgslcblas.so
>>>> libgslcblas.so.0  libgslcblas.so.0.0.0  libgsl.la  libgsl.so
>>>> libgsl.so.0  libgsl.so.0.15.0  libigraph.a  libigraph.la  libigraph.so
>>>>  libigraph.so.0  libigraph.so.0.0.0  pkgconfig
>>>>
>>>> The include files are also in their place. I suspect it has to do with
>>>> bad registration of the shared library. But why didn't I get any
>>>> message at installation, or when I compiled my program?
>>>> I wanted to check the cache of ldconfig but strangely enough the
>>>> command is not available.
>>>> Looking at this it all seems like a big hurdle and I don't have much
>>>> time right now:
>>>> http://www.faqs.org/docs/Linux-HOWTO/Program-Library-HOWTO.html#AEN115
>>>> I am not very good at libtools, perhaps you can give me some help
>>>> running my program? JJ
>>>>
>>>> Thanks!
>>>>
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>>>
>>
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>
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-- 
Gabor Csardi <address@hidden>     UNIL DGM