z.lib problems while porting qt creator projet to windows

Question

I am trying to port a Qt5.9 project from Mac to Windows 10. I was able to compile the project easily in a ubuntu installation. While trying to build it for windows, i had problems with finding zlib include headers with

#include<zlib.h>

That i corrected after following answers here on Stack to

#include<QtZlib/zlib.h> 

Now i have problems in LINK phase, it can not open the file z.lib

Problem is i downloaded zlib packages, builds, source code and could not find a z.lib. Only different named libs. Searching in google i could only find people with the same problem, z.lib is not one of the libs included in zlib installation.

This is my project file:

TEMPLATE = app

QT += qml quick widgets websockets

CONFIG += c++11

SOURCES += \
    main.cpp \
    api.cpp \
    app.cpp

HEADERS += \
    api.hpp \
    app.hpp

RESOURCES += qml.qrc


LIBS += -lz

I tried putting all possible dll and lib files in the project folder. None of them is named z.lib though.

Answer 1

I managed to solve my problem updating my Qt installation to use MinGw 5.3 32bit. I was using VisualStudio 2015 as the compiler before.

Only changing the compiler to MinGw (g++) 5.3 made everything work with the same pro file i posted in the original question. Thanks everybody who tried to help!

Answer 2

The symbols for zlib are already part of the qt libraries. As long as you do not try to link the zlib explicitly it should work. At least it does work for me.

add to your project file:

!win32 {
    LIBS += -lz
}