Date:	Thu, 13 Aug 1998 10:10:18 +0200 (WET)
From:	Andris Pavenis <pavenis AT lanet DOT lv>
To:	djgpp AT delorie DOT com
Subject:	Re: please help me to compile an Objective-C program
In-Reply-To:	<35d25c2c.9025265@news.neosoft.com>
Message-ID:	<Pine.A32.3.91.980813100507.131512A-100000@ieva05.lanet.lv>
MIME-Version:	1.0

On Thu, 13 Aug 1998, Flatulator wrote:

> Hi.  I'm new to Objective-C and I'm trying to compile this sample
> program.  I'm using DJGPP v2 to do it.  I did everything perfectly as
> far as I can tell and I got some "undefined reference" error messages.
> The files in question are main.m, Printer.m, and Printer.h.  
> Here's what I'm typing to compile:
> gcc -c main.m (no problem)
> gcc -c Printer.m (no problem)
> gcc -lobjc main.o Printer.o (Problem occurs here)
> 
> Here are the error messages:
> 
> main.o(.text+0x31):main.m: undefined reference to `objc_get_class'
> main.o(.text+0x3c):main.m: undefined reference to `objc_msg_lookup'
> main.o(.text+0x54):main.m: undefined reference to `objc_msg_lookup'
> main.o(.text+0x77):main.m: undefined reference to `objc_msg_lookup'
> main.o(.text+0x9f):main.m: undefined reference to `objc_msg_lookup'
> main.o(.text+0xc4):main.m: undefined reference to `objc_msg_lookup'
> main.o(.text+0xed):main.m: undefined reference to `__objc_exec_class'
> Printer.o(.text+0x20):Printer.m: undefined reference to
> `objc_msg_lookup_super'
> Printer.o(.text+0x41):Printer.m: undefined reference to
> `objc_msg_lookup'
> Printer.o(.text+0xb1):Printer.m: undefined reference to
> `objc_msg_lookup'
> Printer.o(.text+0x105):Printer.m: undefined reference to
> `__objc_exec_class'
> Printer.o(.text+0x110):Printer.m: undefined reference to
> `__objc_class_name_Obje
> ct'
> 
> 
> I would be ever so grateful if some kind soul could help me compile
> this program.  I feel certain it's a link time error.  The contents of
> the files in this program follow.  Also, I tried compiling this in gcc
> in some UNIX and I got the exact same problem.
> 
> 


Which version of gcc are You using. I'm not specialist in Objective C
but compiling and linking for DJGPP with both gcc-2.8.1 and egcs-2.91.93
was successfull (however with warnings). And also program looks working.

Output of command:  gcc -v main.m Printer.m -lobjc -o test 

Reading specs from c:/djgpp/lib/gcc-lib/djgpp/egcs-291.53/specs
gcc version egcs-2.91.53 19980803 (gcc2 ss-980609 experimental)
 c:/djgpp/lib/gcc-lib/djgpp/egcs-291.53/cpp.exe -lang-objc -v -isystem 
c:/djgpp/bin/include -undef -D__OBJC__ -D__GNUC__=2 -D__GNUC_MINOR__=91 
-Dunix -Di386 -DGO32 -DMSDOS -DDJGPP=2 -D__unix__ -D__i386__ -D__GO32__ 
-D__MSDOS__ -D__DJGPP__=2 -D__unix -D__i386 -D__GO32 -D__MSDOS 
-D__DJGPP=2 -Asystem(unix) -Asystem(msdos) -Acpu(i386) -Amachine(i386) 
-Asystem(unix) -Acpu(i386) -Amachine(i386) -Di386 -D__i386 -D__i386__ 
main.m c:/djgpp/tmp\ccyuqGTe.i
GNU CPP version egcs-2.91.53 19980803 (gcc2 ss-980609 experimental) 
(80386, BSD syntax)
#include "..." search starts here:
#include <...> search starts here:
 c:/djgpp/include
 c:/djgpp/lib/gcc-lib/djgpp/egcs-291.53/include
 c:/djgpp/include
End of search list.
main.m:1: warning: using `#import' is not recommended
The fact that a certain header file need not be processed more than once
should be indicated in the header file, not where it is used.
The best way to do this is with a conditional of this form:

  #ifndef _FOO_H_INCLUDED
  #define _FOO_H_INCLUDED
  ... <real contents of file> ...
  #endif /* Not _FOO_H_INCLUDED */

Then users can use `#include' any number of times.
GNU C automatically avoids processing the file more than once
when it is equipped with such a conditional.
 c:/djgpp/lib/gcc-lib/djgpp/egcs-291.53/cc1obj.exe 
c:/djgpp/tmp\ccyuqGTe.i -quiet -dumpbase main.m -version -lang-objc -o 
c:/djgpp/tmp\ccnjNul1.s
GNU Obj-C version egcs-2.91.53 19980803 (gcc2 ss-980609 experimental) 
(djgpp) compiled by GNU C version egcs-2.91.53 19980803 (gcc2 ss-980609 
experimental).
main.m: In function `main':
main.m:4: warning: return type of `main' is not `int'
 c:/djgpp/bin/as.exe -o c:/djgpp/tmp\ccdVc0MZ.o c:/djgpp/tmp\ccnjNul1.s
 c:/djgpp/lib/gcc-lib/djgpp/egcs-291.53/cpp.exe -lang-objc -v -isystem 
c:/djgpp/bin/include -undef -D__OBJC__ -D__GNUC__=2 -D__GNUC_MINOR__=91 
-Dunix -Di386 -DGO32 -DMSDOS -DDJGPP=2 -D__unix__ -D__i386__ -D__GO32__ 
-D__MSDOS__ -D__DJGPP__=2 -D__unix -D__i386 -D__GO32 -D__MSDOS 
-D__DJGPP=2 -Asystem(unix) -Asystem(msdos) -Acpu(i386) -Amachine(i386) 
-Asystem(unix) -Acpu(i386) -Amachine(i386) -Di386 -D__i386 -D__i386__ 
Printer.m c:/djgpp/tmp\ccyuqGTe.i
GNU CPP version egcs-2.91.53 19980803 (gcc2 ss-980609 experimental) 
(80386, BSD syntax)
#include "..." search starts here:
#include <...> search starts here:
 c:/djgpp/include
 c:/djgpp/lib/gcc-lib/djgpp/egcs-291.53/include
 c:/djgpp/include
End of search list.
Printer.m:1: warning: using `#import' is not recommended
The fact that a certain header file need not be processed more than once
should be indicated in the header file, not where it is used.
The best way to do this is with a conditional of this form:

  #ifndef _FOO_H_INCLUDED
  #define _FOO_H_INCLUDED
  ... <real contents of file> ...
  #endif /* Not _FOO_H_INCLUDED */

Then users can use `#include' any number of times.
GNU C automatically avoids processing the file more than once
when it is equipped with such a conditional.
 c:/djgpp/lib/gcc-lib/djgpp/egcs-291.53/cc1obj.exe 
c:/djgpp/tmp\ccyuqGTe.i -quiet -dumpbase Printer.m -version -lang-objc -o 
c:/djgpp/tmp\ccnjNul1.s
GNU Obj-C version egcs-2.91.53 19980803 (gcc2 ss-980609 experimental) 
(djgpp) compiled by GNU C version egcs-2.91.53 19980803 (gcc2 ss-980609 
experimental).
 c:/djgpp/bin/as.exe -o c:/djgpp/tmp\ccdpFwY6.o c:/djgpp/tmp\ccnjNul1.s
 c:/djgpp/lib/gcc-lib/djgpp/egcs-291.53/collect2.exe -o test 
c:/djgpp/lib/crt0.o -L. -Lc:/djgpp/lib/gcc-lib/djgpp/egcs-291.53 
-Lc:/djgpp/bin -Lc:/djgpp/lib c:/djgpp/tmp\ccdVc0MZ.o 
c:/djgpp/tmp\ccdpFwY6.o -lobjc -lgcc -lc -lgcc -Tdjgpp.djl
 c:/djgpp/bin/stubify.exe -v test
stubify for djgpp V2.X executables, Copyright (C) 1995 DJ Delorie
stubify: test -> test.000 -> test.exe

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