[ECOS] Re: configtool for linux building problems.

[John Dallaway <john@dallaway.org.uk>]

Hi David

On 22/06/12 19:26, David Fernandez wrote:

>>> 2.- Edit the makefile.gnu in ecos/host/tools/configtool/standalone, and
>>> add to the line EXTRALDFLAGS, at the end, after leaving a space, -lX11
>>> 
>> I have not found -lX11 to be necessary. The invocation of wx-config
>> within makefile.gnu should return all the flags necessary to link with
>> the X window system. Which Linux distro and version are you using? Can
>> you forward the link-time error you observe without this change
>> (including all the command-line arguments) please?
> 
> This is the "simplified" output:
> 
> c++ -o configtool <lots-of-files.o>  -LTCLDIR_use_system/lib -L/usr/local/lib
> -l<other-libs>... -ltcl `/usr/local/bin/wx-config --libs std,gizmos`
> /usr/bin/ld: /usr/local/lib/libwx_gtk2_core-2.8.a(corelib_utilsx11.o):
> undefined reference to symbol 'XGetWindowAttributes'
> /usr/bin/ld: note: 'XGetWindowAttributes' is defined in DSO
> /usr/lib/libX11.so.6 so try adding it to the linker command line
> /usr/lib/libX11.so.6: could not read symbols: Invalid operation
> collect2: ld returned 1 exit status
> make: *** [/<my-build -folder>] Error 1
> 
> I compiled this in Fedora14+wxGTK-2.8.12 and Fedora15+wxGTK-2.8.8, and I
> get the same problem in both of them (both wxGTK were compiled from
> sources and installed in /usr/local, I know that /usr/local/bin is in
> the PATH, but my LD_LIBRARY_PATH is empty, as I rely in the config
> scripts for wx and tcl).

This is almost certainly due to recent Fedora builds of GNU ld using
different DSO-linking semanics. Ref:

  http://fedoraproject.org/wiki/Features/ChangeInImplicitDSOLinking

Specifying -lX11 explictly for Linux builds seems reasonable and should
be safe for other users.

I've attached a patch at:

  http://bugs.ecos.sourceware.org/show_bug.cgi?id=1001613

Thank you for reporting this.

John Dallaway
eCos maintainer
http://www.dallaway.org.uk/john

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