Re: Bug trying to compile a C++ program with libjpeg

Re: Bug trying to compile a C++ program with libjpeg

[Martin v. Loewis]

> g++ -v --save-temps -ljpeg *.cpp

Thanks for your bug report. Unfortunately, you did not report the
error you are getting. Looking at your command line, I see that you
did not mention what the output file should be. Typically, g++ is
invoked with a -o option when linking; please see the gcc manual for
details.

Regards,
Martin
>From law@cygnus.com Thu Jul 01 12:41:00 1999
From: Jeffrey A Law <law@cygnus.com>
To: Alexandre Oliva <oliva@dcc.unicamp.br>
Cc: Stephane Conversy <Stephane.Conversy@lri.fr>, egcs-bugs@egcs.cygnus.com, egcs-patches@egcs.cygnus.com
Subject: Re: compile and install bugs on irix 
Date: Thu, 01 Jul 1999 12:41:00 -0000
Message-id: <30399.930857885@upchuck.cygnus.com>
References: <oryah0nr6y.fsf@saci.lsd.dcc.unicamp.br>
X-SW-Source: 1999-07/msg00025.html
Content-length: 578

  In message < oryah0nr6y.fsf@saci.lsd.dcc.unicamp.br >you write:
  > On Jul  1, 1999, Jeffrey A Law <law@cygnus.com> wrote:
  > 
  > > OK.  Go ahead and check it in then.
  > 
  > Done.  BTW, shouldn't it be checked in the trunk too?  I ask because
  > last week's changes haven't been checked in there.  Even though we're
  > going to wipe texinfo out of our tree, I'd better keep then in sync
  > before we do.  Would you mind if I updated the trunk with the latest
  > branch changes?
I'd prefer not to check in any texinfo related changes to the mainline
sources.  

jeff

Re: Bug trying to compile a C++ program with libjpeg

[Kendrick Hamilton]

The makers of Libjpeg already sent me the solution. The header files for
libjpeg do not have the required extern "C" to allow for the use of C++
directly. If you are writing a C++ program that uses libjpeg, you need to
use the following code to include the header files in the program:

	#ifdef __cplusplus      //include the jpeg library as a C file.
	extern "C"{
	#endif
	#include<jpeglib.h>
	#ifdef __cplusplus
	}
	#endif

This requirement is not well documented ad was the source of the problems.

 Also note, I was allowing the compiler to use the default output file,
a.out. That is why it did not have a -o option when linking.
Regards,
Kendrick Hamilton

On Thu, 1 Jul 1999, Martin v. Loewis wrote:

> > g++ -v --save-temps -ljpeg *.cpp
> 
> Thanks for your bug report. Unfortunately, you did not report the
> error you are getting. Looking at your command line, I see that you
> did not mention what the output file should be. Typically, g++ is
> invoked with a -o option when linking; please see the gcc manual for
> details.
> 
> Regards,
> Martin
>