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Date: Thu, 05 Apr 2001 11:09:56 -0400
To: jonadab AT bright DOT net, cygwin AT cygwin DOT com
From: "Larry Hall (RFK Partners, Inc)" <lhall AT rfk DOT com>
Subject: Re: libpng
In-Reply-To: <3ACC380B.17460.433A2EC@localhost>
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At 09:16 AM 4/5/2001, Jonadab the Unsightly One wrote:

>'ello.
>
>To get some practice compiling stuff and getting it to work
>in cygwin, I downloaded the Persistence of Vision source
>so I can start with that.  It includes zlib (which seems
>to have built with no problems) and libpng (which seems
>more complicated).  There are a number of makefiles, but
>only three of them use gcc.  Of those three, one is for
>a certain version of Solaris; another is for Linux, and
>the third for OS/2.  I figured cygwin is closer to Linux
>than either of those others (yes?  no?  Is that still not
>close enough?) and chose that one, but partway through I 
>get the following:
>
>cc1.exe: warning: -fPIC ignored for target (all code is position independent)
>cc1.exe: warning: -fPIC ignored for target (all code is position independent)
>cc1.exe: warning: -fPIC ignored for target (all code is position independent)
>cc1.exe: warning: -fPIC ignored for target (all code is position independent)
>cc1.exe: warning: -fPIC ignored for target (all code is position independent)
>cc1.exe: warning: -fPIC ignored for target (all code is position independent)
>cc1.exe: warning: -fPIC ignored for target (all code is position independent)
>cc1.exe: warning: -fPIC ignored for target (all code is position independent)
>cc1.exe: warning: -fPIC ignored for target (all code is position independent)
>cc1.exe: warning: -fPIC ignored for target (all code is position independent)
>cc1.exe: warning: -fPIC ignored for target (all code is position independent)
>cc1.exe: warning: -fPIC ignored for target (all code is position independent)
>cc1.exe: warning: -fPIC ignored for target (all code is position independent)
>cc1.exe: warning: -fPIC ignored for target (all code is position independent)
>cc1.exe: warning: -fPIC ignored for target (all code is position independent)
>Cannot export _bss_end__: symbol not defined
>Cannot export _bss_start__: symbol not defined
>Cannot export _data_end__: symbol not defined
>Cannot export _data_start__: symbol not defined
>collect2: ld returned 1 exit status
>make: *** [libpng.so.2.1.0.3] Error 1
>
>For context, I think the last couple of things that happened
>before that are as follows:
>
>gcc -c -I../zlib -Wall -O3 -funroll-loops   -fPIC -o pngpread.pic.o 
>pngpread.c
>gcc -shared -Wl,-soname,libpng.so.2 -o libpng.so.2.1.0.3 \
>  png.pic.o pngset.pic.o pngget.pic.o pngrutil.pic.o pngtrans.pic.o 
>pngwutil.pic.
>o pngread.pic.o pngrio.pic.o pngwio.pic.o pngwrite.pic.o pngrtran.pic.o 
>pngwtran
>.pic.o pngmem.pic.o pngerror.pic.o pngpread.pic.o -L../zlib -lz -lm -lc
>
>Does anyone have a makefile that works for libpng under cygwin,
>or any advice for how to create one (bearing in mind that my
>experience with make is less than my experience with cygwin)?
>I have gcc version 2.95.2-5


I believe Charles Wilson has contributed libpng to Cygwin.  You can get it
and the sources used to build it via setup (www.cygwin.com).  Regarding
your question about which platform Cygwin is closer to.  The answer is,
generally, Linux.  That doesn't mean, however, that you should expect Cygwin
to act and work like Linux in all cases.  Your best bet when building a 
package is to run "configure" provided with most packages.  This should 
create you a makefile properly configured for your environment.  It takes
the guess work out of things.


Larry Hall                              lhall AT rfk DOT com
RFK Partners, Inc.                      http://www.rfk.com
118 Washington Street                   (508) 893-9779 - RFK Office
Holliston, MA 01746                     (508) 893-9889 - FAX


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