Two solutions:
a) link using 'gcc -static'. You must also define ZLIB_STATIC (see
/usr/doc/Cygwin/libpng-x.x.x.README).
OR
b) DON'T define PNG_STATIC.
--Chuck
"Jong B. Lee" wrote:
>
> Happy New Year !!
>
> I'm writing a program using png library.
>
> But, gcc complains that png_read_destroy and png_write_destroy are undefined.
>
> How can I fix it?
>
> I have the latest and clean cygwin installed.
>
> Here's a sample c file and link error :
>
> ------------------------------------
> /* sample png.c */
> #include <png.h>
>
> int main()
> {
> #ifdef __CYGWIN__
> #define PNG_STATIC
> #endif
>
> png_structp pp;
> png_infop info;
> png_read_end(pp, info);
> png_read_destroy(pp, info, NULL);
> png_write_destroy (pp);
>
> return 0;
> }
> -------------------------------------
> $ gcc -W -g png.c -lpng -o png
>
> /c/WINDOWS/TEMP/ccFXASfF.o(.text+0x30): undefined reference to `png_read_destroy'
> /c/WINDOWS/TEMP/ccFXASfF.o(.text+0x3f): undefined reference to `png_write_destroy'
> collect2: ld returned 1 exit status
> ===============================
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