CODEWITHSUNDEEP
qtqt-creatorlibpng
Meetai.com
Meetai.com

Reputation: 6928

Linking with libpng in Qt

I'm trying to compile a project that uses both the Qt framework and libpng. I was having errors with a previous version of libpng so I downloaded a newer code-base and now I get the following errors when I try to build my project:

Running build steps for project mytool-win-cli...
Configuration unchanged, skipping qmake step.
Starting: "C:\QtSDK\mingw\bin\mingw32-make.exe" 
C:/QtSDK/mingw/bin/mingw32-make -f Makefile.Debug
mingw32-make[1]: Entering directory `C:/_src/mytool-win-cli-build-desktop-Qt_4_7_4_for_Desktop_-_MinGW_4_4__Qt_SDK__Debug'
g++ -mthreads -Wl,-subsystem,windows -o debug\mytool-win-cli.exe debug/main.o  -L"c:\QtSDK\Desktop\Qt\4.7.4\mingw\lib" -lmingw32 -lqtmaind -lpng -lQtGuid4 -lQtCored4 -LC:\OpenSSL-Win32_full\lib 
c:/qtsdk/mingw/bin/../lib/gcc/mingw32/4.4.0/../../../libpng.a(libpng14_la-pngread.o): In function `png_create_read_struct_2':
/usr/src/packages/libpng/14/libpng-1.4.8-1/src/libpng-1.4.8/pngread.c:90: undefined reference to `setjmp'
c:/qtsdk/mingw/bin/../lib/gcc/mingw32/4.4.0/../../../libpng.a(libpng14_la-pngerror.o): In function `png_default_warning':
/usr/src/packages/libpng/14/libpng-1.4.8-1/src/libpng-1.4.8/pngerror.c:361: undefined reference to `__getreent'
/usr/src/packages/libpng/14/libpng-1.4.8-1/src/libpng-1.4.8/pngerror.c:362: undefined reference to `__getreent'
c:/qtsdk/mingw/bin/../lib/gcc/mingw32/4.4.0/../../../libpng.a(libpng14_la-pngerror.o): In function `png_default_error':
/usr/src/packages/libpng/14/libpng-1.4.8-1/src/libpng-1.4.8/pngerror.c:297: undefined reference to `__getreent'
/usr/src/packages/libpng/14/libpng-1.4.8-1/src/libpng-1.4.8/pngerror.c:298: undefined reference to `__getreent'
/usr/src/packages/libpng/14/libpng-1.4.8-1/src/libpng-1.4.8/pngerror.c:297: undefined reference to `__getreent'
c:/qtsdk/mingw/bin/../lib/gcc/mingw32/4.4.0/../../../libpng.a(libpng14_la-pngerror.o):/usr/src/packages/libpng/14/libpng-1.4.8-1/src/libpng-1.4.8/pngerror.c:298: more undefined references to `__getreent' follow
collect2: ld returned 1 exit status
mingw32-make[1]: Leaving directory `C:/_src/mytool-win-cli-build-desktop-Qt_4_7_4_for_Desktop_-_MinGW_4_4__Qt_SDK__Debug'
mingw32-make[1]: *** [debug\mytool-win-cli.exe] Error 1
mingw32-make: *** [debug] Error 2
The process "C:\QtSDK\mingw\bin\mingw32-make.exe" exited with code 2.
Error while building project mytool-win-cli (target: Desktop)
When executing build step 'Make'

I suspect there has to be a problem with versions between the included libpng sources and the mingw compiled one, but I can't really tell. What am I doing wrong?

Upvotes: 4

Views: 3828

Answers (2)

zero
zero

Reputation: 193

When you build Qt, QtGui is compile with libpng, it is static link in libQtGui.so

You should not have to link libpng again I think.

in src/gui/ you make and make install, libQtGui.so should be in your lib.

Upvotes: 0

synthesizerpatel
synthesizerpatel

Reputation: 28036

So, there's really no reason to do that, Qt ships with qpng already. QImage will both read and write them.

Upvotes: 2

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