Re: gcc command works, GnuStep makefile fails

[David Ayers]

Sergei Gnezdov wrote:
> The following command compiles a simple Hello world program (yes, I
> want to include mysql):
>
> gcc Source.m -lobjc -lpthread -lmysqlclient -lz -L/usr/local/lib/mysql
>
> The following GNUmakefile compiles the same file, but application
> crashes.  It started to crash, when I added mysql to GNUmakefile:
>
> -----
> include ${GNUSTEP_MAKEFILES}/common.make
>
> ADDITIONAL_OBJCFLAGS= -Wno-import -Wall
>
> TOOL_NAME = app
> app_OBJC_FILES = Source.m
> app_INCLUDE_DIRS = -I/usr/local/include/mysql
> app_TOOL_LIBS = -lecgi -lmysqlclient -lz
> app_LIB_DIRS = -L/usr/local/lib/mysql
>
> include ${GNUSTEP_MAKEFILES}/tool.make
> -----
>
> Error message:
>
> Bus error (core dumped)
>
> Another problem is that I have no clue what kind of command line
> GNUmakefile generates.

I had a similar crash with mysqlclient.  My problem was, that libobjc 
and libmysqlclient both export hash_next functions and the libobjc was 
calling into the mysql version during class initialization.  You could 
either "work around" this by ordering the linked libraries in way that 
happens to work (I don't know whether this can be done with 
gnustep-make) or you can try creating another C wrapper library for 
mysqlclient and avoid linking -lobjc and -lmysqlclient in the same 
executable which seems to work around the issue for us currently.

GCC 4.0 will call new objc_ prefixed hash functions but even 4.1 will 
probably still have the original version for binary compatibility, so 
you still run the risk that the mysqlclient may call into the objc 
version :-/.

If you have the possibility of building your own libobjc then you could 
apply similar patches and remove the non-prefixed versions.

For more information see:

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19024

Cheers,
David Ayers