libpng issues

[Marco Alanen]

Gerrit P. Haase wrote:
 > Marco Alanen wrote:
 >
 >> Gerrit P. Haase wrote:
 >>
 >>> Marco Alanen wrote:
 >>>
 >>>> After successfully porting our application from Linux to cygwin,
 >>>> most of the functions work, except for one thing - png images. As
 >>>> soon as I call  png_create_read_struct, the application will
 >>>> imediately hang and start using up all available CPU power. This
 >>>> happens with both libpng10 and libpng12.
 >>>>
 >>>> This is the call we make:
 >>>> png_structp png_ptr = png_create_read_struct (PNG_LIBPNG_VER_STRING,
 >>>> (png_voidp)0, 0, 0);
 >>>>
 >>>> Anybody who knows anything about it, or knows what more information
 >>>> I should provide?
 >>>
 >>>
 >>>
 >>>
 >>> Simple testcase (compilable snippet), please?
 >>>
 >>> Gerrit
 >>
 >>
 >>
 >> Some simple code:
 >> #include <stdio.h>
 >> #include <png.h>
 >>
 >> int main(int argc, char **argv)
 >> {
 >>         png_structp png_ptr = png_create_read_struct
 >> (PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
 >>
 >>         return 0;
 >> }
 >>
 >> Compiled with:
 >> gcc -o pngtest pngtest.c -mno-cygwin -mwin32 -mwindows -lpng
 >
 >
 > And you have libpng installed?
 >
 > $ ls /usr/lib/mingw/*png*
 > ls: /usr/lib/mingw/*png*: No such file or directory
 >
 > $ ls /usr/lib/w32api/*png*
 > ls: /usr/lib/w32api/*png*: No such file or directory
 >
 > Me not and therefore I cannot test it:
 > $ gcc -o pngtest pngtest.c -mno-cygwin -mwin32 -mwindows -lpng
 > pngtest.c:2:17: png.h: No such file or directory
 > ...

Yes it's installed, otherwise it wouldn't compile nor run :)

 > Please contact the distributor of your MinGW libpng since this library
 > is not distributed with Cygwin it is not supported here.

Ok. I just thought that since it's included in the cygwin installer, 
someone here might have an idea (or previous experiences) about this.

 > BTW, using the Cygwin libpng without -mno-cygwin works ok and using this
 > switch doesn't port your software to Cygwin;)

Ok, mingw enviroment :)


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