[cairo] Uninitialized Values

[Paul Menzel]

Dear Eric,


Am 03.06.2018 um 04:30 schrieb cecashon at aol.com:

> With valgrind I get a lot of uninitialised values with the following program. Everything draws fine. If the radial pattern code gets commented out then these errors don't occur. A little stuck on this one.

> ==3380== Use of uninitialised value of size 4
> ==3380==    at 0x473B1A5: crc32 (in /lib/i386-linux-gnu/libz.so.1.2.8)
> ==3380==    by 0x456E374: ??? (in /lib/i386-linux-gnu/libpng12.so.0.54.0)
> ==3380==    by 0x4576E3F: png_write_chunk_data (in /lib/i386-linux-gnu/libpng12.so.0.54.0)
> ==3380==    by 0x4576FE5: png_write_chunk (in /lib/i386-linux-gnu/libpng12.so.0.54.0)
> ==3380==    by 0x457777D: ??? (in /lib/i386-linux-gnu/libpng12.so.0.54.0)
> ==3380==    by 0x45794A4: ??? (in /lib/i386-linux-gnu/libpng12.so.0.54.0)
> ==3380==    by 0x4579B3F: ??? (in /lib/i386-linux-gnu/libpng12.so.0.54.0)
> ==3380==    by 0x4579E60: ??? (in /lib/i386-linux-gnu/libpng12.so.0.54.0)
> ==3380==    by 0x457DD3F: png_write_row (in /lib/i386-linux-gnu/libpng12.so.0.54.0)
> ==3380==    by 0x457DF7E: png_write_image (in /lib/i386-linux-gnu/libpng12.so.0.54.0)
> ==3380==    by 0x4110033: ??? (in /usr/lib/i386-linux-gnu/libcairo.so.2.11400.6)
> ==3380==    by 0x4110A6A: cairo_surface_write_to_png (in /usr/lib/i386-linux-gnu/libcairo.so.2.11400.6)
> ==3380==  Uninitialised value was created by a stack allocation
> ==3380==    at 0x440AB5E: ??? (in /usr/lib/i386-linux-gnu/libpixman-1.so.0.33.6)
> 
> /*
>      gcc -Wall -Wextra -g -O0 cairo_test1.c -o cairo_test1 `pkg-config --cflags --libs cairo` -lm
> 
>      valgrind --leak-check=full --show-leak-kinds=all --track-origins=yes ./cairo_test1
> 
>      Tested on 32bit Ubuntu16.04
> */

[…]

Please install the debug symbols, and als try the Ubuntu 18.04 with more 
recent versions so to make sure, the issue still persists.


Kind regards,

Paul