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Forum Topic - Issue while building a shared library:

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Girisha SG

11/18/2010 9:34 AM

post75097

Issue while building a shared library

I have a project that builds couple of library project and then it builds an application project that uses these library
 files, I have the following issue,

I am able to compile the libraries in static mode and able to link and crate an executable however if I try building 
shared library I am getting error ''undefined reference to XYZ", what might be the reason ???

Ryan Mansfield(deleted)

11/18/2010 9:38 AM

post75100

Re: Issue while building a shared library

On 10-11-18 09:34 AM, Girisha SG wrote:
> I have a project that builds couple of library project and then it
> builds an application project that uses these library files, I have the
> following issue,
>
> I am able to compile the libraries in static mode and able to link and
> crate an executable however if I try building shared library I am
> getting error ''undefined reference to XYZ", what might be the reason ???

The reason you're not resolving the dependencies the shared object has 
on other libraries. You need to link against the libraries that provide 
the definitions for XYZ using the -l option.

You don't see this when you create a static archive because the linker 
does not resolve the libraries dependencies as an archive is a just 
format containing individual object files.

Regards,

Ryan Mansfield

Girisha SG

11/19/2010 2:15 AM

post75262

Re: Issue while building a shared library

HI,
Thanks for the reply.

I have libraries B,C,D,E,F and application program A that uses these libraries and I have the following queries,

I I build only the libraries I am not getting any error but when I try to build & link them with the application I am 
getting the 'undefined reference to XYZ...'

While building the libraries I am getting the warning 'undefined reference to XYZ...'
Even if I link the dependent .so while compiling I am getting the same error.

Girisha SG

11/19/2010 4:46 AM

post75265

Re: Issue while building a shared library

Finally I am able to build it :) thanks for all your help.

I have following queries,
1. Whether we have libgcc.so file for ARMV7 that defines '__aeabi_uldivmod' symbol ?

2. I am having multiple folders and one .so within each folder, while building the executable I am giving the .so file 
paths relative to the current folder, suppose I copy the .so & .exe files in the same folder on the target and run the 
executable it works. Now suppose I want to retain the existing command while building the executable but while running I
 want all these .so files to be present in some other folder, how can I do this & how OS/exe comes to know where are the
 .so files and how to load it?

This will help my development using QNX.

Ryan Mansfield(deleted)

11/19/2010 7:54 AM

post75268

Re: Issue while building a shared library

On 10-11-19 04:46 AM, Girisha SG wrote:
> Finally I am able to build it :) thanks for all your help.
>
> I have following queries,
> 1. Whether we have libgcc.so file for ARMV7 that defines
> '__aeabi_uldivmod' symbol ?

Yes.. libgcc.a has this routine..

ntoarm-nm 
/opt/qnx650/host/linux/x86/usr/lib/gcc/arm-unknown-nto-qnx6.5.0eabi/4.4.2/pic/libgcc.a 
| grep __aeabi_uldivmod
00000000 T __aeabi_uldivmod

>
> 2. I am having multiple folders and one .so within each folder, while
> building the executable I am giving the .so file paths relative to the
> current folder, suppose I copy the .so & .exe files in the same folder
> on the target and run the executable it works. Now suppose I want to
> retain the existing command while building the executable but while
> running I want all these .so files to be present in some other folder,
> how can I do this & how OS/exe comes to know where are the .so files and
> how to load it?

Use LD_LIBRARY_PATH to tell the dynamic linker where to find the shared 
objects on your target,

Regards,

Ryan Mansfield

Girisha SG

11/30/2010 3:01 AM

post76397

Re: Issue while building a shared library

After linking gcc library __aeabi_uldivmod error has gone but now i am getting the following error

ldd:FATAL: Unresolved symbol "__gnu_uldivmod_helper" called from Executable

Which library should we link to resolve this issue ?

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