From: not AT an DOT email DOT address DOT com (Flatulator)
Newsgroups: comp.os.msdos.djgpp,comp.lang.objective-c
Subject: please help me to compile an Objective-C program
Date: Thu, 13 Aug 1998 03:26:54 GMT
Organization: NeoSoft, Inc.  
Lines: 97
Message-ID: <35d25c2c.9025265@news.neosoft.com>
NNTP-Posting-Host: as5200-port-96.no.neosoft.com
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Precedence: bulk

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.


--------Here is main.m------------
#import "Printer.h"

void main()
{
   id printer = [[Printer alloc] init];
   [printer addStringValue:"Hello World!"];
   [printer print];
   [printer free];
}



--------Here's Printer.m--------------
#import "Printer.h"

@implementation Printer
-init
{
  [super init];
  [self clear];
  return self;
}

- addStringValue:(const char*) astring
{
  strcat(buffer, astring);
  return self;
}

- print
{
 printf("%s\n",buffer);
  [self clear];
  return self;
}

- clear
{
  strcpy(buffer, "");
  return self;
}

@end
-------------Here's Printer.h---------------
#import <objc/Object.h>

@interface Printer: Object
{
   char buffer[100];
}


- init;
- addStringValue: (const char *)astring;
- print;
- clear;

@end