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Message-ID: <3C3DD155.5010108@ece.gatech.edu>
Date: Thu, 10 Jan 2002 12:37:25 -0500
From: Charles Wilson <cwilson AT ece DOT gatech DOT edu>
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To: "Gerrit P. Haase" <gerrit AT familiehaase DOT de>
CC: cygwin AT cygwin DOT com
Subject: Re: libpng problems with png_info_init, png_read_destroy
References: <757896744 DOT 20020110124749 AT familiehaase DOT de> <1799332659 DOT 20020110131145 AT familiehaase DOT de> <20020110145308 DOT A7436 AT infosat DOT net> <13712653054 DOT 20020110140705 AT familiehaase DOT de>
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'man libpng' reveals:

png_read_init ---> png_create_read_struct
png_write_init ---> png_create_write_struct
png_info_init --> png_create_info_struct
png_read_destroy --> png_destroy_read_struct
png_write_destroy --> png_destroy_write_struct

The old methods have been deprecated.  They are currently marked 
INTERNAL and are not exported by the DLL, but  will be completely 
removed in the libpng-2.0.0 release.

If you MUST continue to use the old methods, then you should 
-DPNG_STATIC -DZLIB_STATIC when compiling, and -static when linking.

--Chuck

Gerrit P. Haase wrote:

>  Jean,
> 
> 2002-01-10 14:01:30, du schriebst:
> 
> 
>>Perhaps this time I can ofer my two cents worth ;)
>>
> 
>>>>Hallo Cygwinners,
>>>>
>>>>I'm getting these undefined references when linking against
>>>>libjpeg import lib:
>>>>
>>>Waddaza want?  Wanted to say> libpng import lib
>>>
>>>
>>>>/stuff/test/mMosaic-src-3.7.2/src/readPNG.c:79: undefined reference to `png_read_destroy'
>>>>/stuff/test/mMosaic-src-3.7.2/src/readPNG.c:94: undefined reference to `png_info_init'
>>>>/stuff/test/mMosaic-src-3.7.2/src/readPNG.c:286: undefined reference to `png_read_destroy'
>>>>
>>>>Are there a known workaround besides linking the libs statically?
>>>>
> 
>>Since you are using .c, I presume that you are including the source
>>and that the .c files do not contain the declerations, but only the
>>implmentations of the code. Errors like your's if freuently
>>encountered when forgetting to include a header file. Make sure that
>>you are not looking for /stuff/test/mMosaic-src-3.7.2/src/readPNG.h
>>instead.
>>
> 
>>It appears that you want to rather include the .h files and add the
>>relevant lib in your link-line.
>>
> 
> No, the problem is that these functions are private and are not exported
> from the dll lib, so I need to link libpng staticallz to get the
> functions, but I want to link against the dynamic lib.
> 
> I found one reference in the archives how to substitute png_info_init
> with png_create_info_struct() but nothing about png_read_destroy().
> 
> 
> Anyway, thank you for your comment, please keep communication on the
> cygwin list as long as it is ontopic there.
> 
> Gerrit
> 



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