Path: utzoo!utgpu!utstat!jarvis.csri.toronto.edu!mailrus!ames!amdahl!pacbell!sactoh0!bkbarret
From: bkbarret@sactoh0.UUCP (Brent K. Barrett)
Newsgroups: comp.lang.c
Subject: Re: TLINK errors (cc/lint were clean)
Summary: Must use externs
Message-ID: <670@sactoh0.UUCP>
Date: 3 Feb 89 03:56:27 GMT
References: <44100021@hcx1>
Organization: Sacramento Public Access, Ca. USA
Lines: 46

In article <44100021@hcx1>, ldh@hcx1.SSD.HARRIS.COM writes:
> 
> Here's one for the UNIX gurus who also know something about TurboC ...
> 
> Have a modularized program lint/cc do not object to the various modules ... TC2
> on the other hand does.
> 
 [ Chomp! ]j
> When invoked as follows, the TurboC 2.0 linker has a 2 major objections:
>     tlink \tc2\lib\c0m main module_a module_b,prog,prog,,\tc2\lib\cm
> 
> 
> 1) variables defined in header.h get linker error messages as follows:
> Error: _A defined in module MAIN.C is duplicated in module MODULE_A.C
> Error: _A defined in module MAIN.C is duplicated in module MODULE_B.C
> 
> 2) Certain basic stuff ends up being "undefined"
> Undefined symbol '_FOPEN' in module MAIN.C
> Undefined symbol '_PRINTF' in module MAIN.C
> 
> What is going on?!  This is the first time I have tried anything modularized on
> TC2 ... 
 
 Turbo C allows global variables to be declared only ONCE. Every
other time they are included in a module, they must be declared as
"extern"als.  Do the following to solve your problem:
 
 1) Place all your variable declarations into your main.c file as
is, then create a file called "extern.h" that lists the same
variable declarations prefixed by "extern."
  e.g.:
 
 float j;

    becomes:

 extern float j;
 
 2) simply #include "extern.h" in all your modules except main.c.

 I'm no Unix guru, but that will solve your TC problems.

-- 
 "Somebody help me! I'm trapped in this computer!"
  
 Brent Barrett ..pacbell!sactoh0!bkbarret GEMAIL: B.K.BARRETT