Can't generate shared library on ubuntu and can't link statically to a static library

sierdzio

Can you share the relevant parts of your .pro files for both issues you mention?

Mohammedbie

Thanks for the fast reply , here are the .pro files :

shared library .pro :

#-------------------------------------------------
#
# Project created by QtCreator 2018-12-11T23:18:12
#
#-------------------------------------------------

QT       -= gui

TARGET = DLLtest
TEMPLATE = lib

DEFINES += DLLTEST_LIBRARY

# The following define makes your compiler emit warnings if you use
# any feature of Qt which as been marked as deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS

# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0

SOURCES += dlltest.cpp

HEADERS += dlltest.h\
        dlltest_global.h

unix {
    target.path = /usr/lib
    INSTALLS += target
}

unix:!macx: LIBS += -L$$PWD/../build-StaticTest-Desktop_Qt_5_8_0_GCC_64bit-Debug/ -lStaticTest

INCLUDEPATH += $$PWD/../StaticTest
DEPENDPATH += $$PWD/../StaticTest

unix:!macx: PRE_TARGETDEPS += $$PWD/../build-StaticTest-Desktop_Qt_5_8_0_GCC_64bit-Debug/libStaticTest.a

Static library .pro :

#-------------------------------------------------
#
# Project created by QtCreator 2018-12-12T01:26:48
#
#-------------------------------------------------

QT       -= gui

TARGET = StaticTest
TEMPLATE = lib
CONFIG += staticlib

# The following define makes your compiler emit warnings if you use
# any feature of Qt which as been marked as deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS

# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0

SOURCES += statictest.cpp

HEADERS += statictest.h
unix {
    target.path = /usr/lib
    INSTALLS += target
}

Test program .pro :

QT += core
QT -= gui

CONFIG += c++11

TARGET = test
CONFIG += console
CONFIG -= app_bundle

TEMPLATE = app

SOURCES += main.cpp

# The following define makes your compiler emit warnings if you use
# any feature of Qt which as been marked deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS

# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0



unix:!macx: LIBS += -L$$PWD/./ -lDLLtest

INCLUDEPATH += $$PWD/../DLLtest
DEPENDPATH += $$PWD/../DLLtest

sierdzio

Hm, code looks good to be honest.

@Mohammedbie said in Can't generate shared library on ubuntu and can't link statically to a static library:

unix:!macx: LIBS += -L$$PWD/../build-StaticTest-Desktop_Qt_5_8_0_GCC_64bit-Debug/ -lStaticTest

Is there a .a in that folder? Perhaps you need to link specifically to .a and not use the general -l flag.

Mohammedbie

@sierdzio

tried adding the following line with the same result :

LIBS += /home/softlock/build-StaticTest-Desktop_Qt_5_8_0_GCC_64bit-Debug/libStaticTest.a

sierdzio

@Mohammedbie said in Can't generate shared library on ubuntu and can't link statically to a static library:

@sierdzio

tried adding the following line with the same result :
LIBS += /home/softlock/build-StaticTest-Desktop_Qt_5_8_0_GCC_64bit-Debug/libStaticTest.a

Sorry I should have been more specific. You can provide full path to -l flag:

LIBS += -l/home/softlock/build-StaticTest-Desktop_Qt_5_8_0_GCC_64bit-Debug/libStaticTest.a

Or, another option is to use the file name specifier:

unix:!macx: LIBS += -L$$PWD/../build-StaticTest-Desktop_Qt_5_8_0_GCC_64bit-Debug/ -l:libStaticTest.a

Still, I don't know if that'll work.

Mohammedbie

@sierdzio

Tried both with the same result too.

Mohammedbie

something I didn't mention as I didn't think it was related , I build the shared library with Qt static library which I built from sources .
Now when I try to build the shared library with the same version of Qt but dynamic it builds and generates .so file and the test application runs normally.
What might cause this ?

sierdzio

@Mohammedbie said in Can't generate shared library on ubuntu and can't link statically to a static library:

something I didn't mention as I didn't think it was related , I build the shared library with Qt static library which I built from sources .
Now when I try to build the shared library with the same version of Qt but dynamic it builds and generates .so file and the test application runs normally.
What might cause this ?

Hm, not sure but maybe your Qt config or mkspecs leak into definitions of your project when qmake is run.

Try adding this in your shared lib .pro file:

CONFIG -= staticlib
CONFIG += shared

Mohammedbie

Thank you very much .
This solved it.

Mohammedbie

@sierdzio sorry for bothering you but one last thing how to convert those lines to a cmake line ?

Thanks in advance

sierdzio

@Mohammedbie said in Can't generate shared library on ubuntu and can't link statically to a static library:

@sierdzio sorry for bothering you but one last thing how to convert those lines to a cmake line ?

Thanks in advance

No idea, I don't know cmake well enough.

Mohammedbie

Ok thanks.

SGaist

Hi,

You set that in the call to add_library.

Mohammedbie

@SGaist

Hi ,
what I understood from cmake documentation is that add_library() configure the current project as a library and don't add an external library what I used instead was target_link_libraries() and it did the job indeed.

SGaist

Ok, from you .pro file it looked like you were generating libraries.