Error: Cannot find -lSDL2

ajcdev

Hello.

I need help regarding my issue trying to link SDL2 in my project and for some reason it's getting errors although I just followed this guide.

This is my code after linking my SDL2 library and include:

QT       += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

CONFIG += c++17

# You can make your code fail to compile if it uses deprecated APIs.
# In order to do so, uncomment the following line.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0

SOURCES += \
    main.cpp \
    aerodesk.cpp

HEADERS += \
    aerodesk.h

FORMS += \
    aerodesk.ui

# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target

win32:CONFIG(release, debug|release): LIBS += -L$$PWD/../../SDL2-2.28.5/i686-w64-mingw32/release/ -lSDL2
else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/../../SDL2-2.28.5/i686-w64-mingw32/debug/ -lSDL2
else:unix: LIBS += -L$$PWD/../../SDL2-2.28.5/i686-w64-mingw32/ -lSDL2

INCLUDEPATH += $$PWD/../../SDL2-2.28.5/i686-w64-mingw32/include/SDL2
DEPENDPATH += $$PWD/../../SDL2-2.28.5/i686-w64-mingw32/include/SDL2

The errors are following below:

:-1: error: cannot find -lSDL2
:-1: error: collect2.exe: error: ld returned 1 exit status
:-1: error: [Makefile.Debug:72: debug/AeroDesk.exe] Error 1

Any help is appreciated!

jsulm

@ajcdev Was the SDL lib built using same compiler you're using?
Also, on Windows your LIBS should look differently, see https://doc.qt.io/qt-6/qmake-variable-reference.html#libs

ajcdev

@jsulm No. I just downloaded the SDL2 from their Github repository.

This is what I have done so far. Now it can't detect the SDL2 library itself:

QT       += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

CONFIG += c++17

# You can make your code fail to compile if it uses deprecated APIs.
# In order to do so, uncomment the following line.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0

SOURCES += \
    main.cpp \
    aerodesk.cpp

HEADERS += \
    aerodesk.h

FORMS += \
    aerodesk.ui

# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target

win32:LIBS += "C:\Users\admin\Documents\SDL2-2.28.5\i686-w64-mingw32\lib\libSDL2.a"

INCLUDEPATH += $$PWD/../../SDL2-2.28.5/i686-w64-mingw32/include/SDL2
DEPENDPATH += $$PWD/../../SDL2-2.28.5/i686-w64-mingw32/include/SDL2

jsulm

@ajcdev said in Error: Cannot find -lSDL2:

win32:LIBS += "C:\Users\admin\Documents\SDL2-2.28.5\i686-w64-mingw32\lib\libSDL2.a"

This is for static library. Do you want to link dynamically? If so, then you have to add *.lib, not *.a

ajcdev

@jsulm Yeah I want to link dynamically.

I tried this:

win32:LIBS += C:\Users\admin\Documents\SDL2-2.28.5\i686-w64-mingw32\lib\*.lib

Now the error is this:

:-1: error: cannot find C:\Users\admin\Documents\SDL2-2.28.5\i686-w64-mingw32\lib*.lib: Invalid argument

jsulm

@ajcdev said in Error: Cannot find -lSDL2:

win32:LIBS += C:\Users\admin\Documents\SDL2-2.28.5\i686-w64-mingw32\lib*.lib

What is this please?! You have to put the file name of your library instead of *.lib...

Are you using MinGW compiler?

ajcdev

@jsulm Yes I am using MinGW compiler. I do apologize since I'm really new when it comes to Qt Creator.

Also I don't have a .lib file in my SDL2 library and they're all .a files. I downloaded the SDL2 that uses MingW from their repository.

jsulm

@ajcdev said in Error: Cannot find -lSDL2:

Now it can't detect the SDL2 library itself

What does this mean? What exactly happens if you try to link the static version?

ajcdev

@jsulm

win32:LIBS += "C:\Users\admin\Documents\SDL2-2.28.5\i686-w64-mingw32\lib\libSDL2.a"

So this is what I used since there's no .lib files in the SDL2 MingW library. What happens is that my SDL2 codes get an error that they become undefined.

aerodesk.cpp:16: error: undefined reference to `SDL_Init'

Christian Ehrlicher

@ajcdev Since your Qt version is 64bit you must also link against the 64bit sdl lib.

ajcdev

@Christian-Ehrlicher I'm not sure how you do that. Do I need to add another library for SDL2 for this?

jsulm

@ajcdev You need to download and use 64bit version of that library. From where exactly did you download it?

ajcdev

@jsulm I downloaded from their Github Repository.

I downloaded the one that comes with the MingW.

Christian Ehrlicher

There is also a64 bit version in the dev zip file. Adjust your path accordingly.

jsulm

@ajcdev Then use the lib in x86_64-w64-mingw32 subfolder. i686-w64-mingw32 is the 32bit version.

ajcdev

@jsulm @Christian-Ehrlicher

Well, my code doesn't work after but I'll figure it out later.

I can say that the linking works properly now. Thanks for your help guys!