linking tool to use a framework : obj_send_msg error

[Thomas Kupper]

Hello,

I just started programming in Objective-C (I do have knowledge of C,  
Java and C++) under Mac OS X and was a bit suprised by the wide use of  
NSLog. But I found log4cocoa which implements the log4j concept in Obj- 
C.

log4cocoa comes with project files for XCode only and since I don't  
have a Mac at work I tought of make it compile under Linux/GNUstep.  
Turned out to be a piece of cake, only three little problems which  
were easy to fix/workaround (on Ubuntu 8.10). So now I have a  
GNUmakefile{preamble,postamble} set of file which let me compile the  
log4cocoa framework without any errors or warnings at all.

Next I created a very minimalistic tool application which uses the  
log4cocoa framework (of course I first installed it into the USER  
domain). Now the linker throws an error message
"Linking tool ocHello ..."
"/home/thomas/GNUstep/Library/Libraries/liblog4cocoa.so: undefined  
reference to 'objc_msgSend'".
"collect2: ld returned 1 exit status"

How can that happen if the framework compiles/links fine. And the tool  
compiles/links fine, too without using the framework.

Can someone give me a hint how I can track down that error?


Have a good time,
Thomas