<![CDATA[Building a 32bit application on a 64bit machine.]]>I'm getting close.

I'm using mkspec linux-g++-32, and the CFLAGS, CXXFLAGS and LFLAGS all have -m32 in them and all of the object files are compiled into 32 bit.

But the linker is still using -L/usr/lib/x86_64-linux-gnu and not -L/usr/lib/i386-linux-gnu and I can not seem to find out how to fix it. Here is a copy of the linker line:

*g++ -m32 -o Test2 main.o -L/usr/lib/x86_64-linux-gnu -L/usr/share/jps-audioproc-third-party/boost/lib -lboost_program_options -lboost_system -lboost_thread -L/usr/lib/i386-linux-gnu -lQtCore -lpthread *

I have tried to remove the x86_64 directory by: LIBS -= -L/usr/lib/x86_64-linux-gnu but that did not work.

I tried changing the Projects->Build Settings->Build Environment->LD_LIBRARY_PATH to /usr/lib/i386-linux-gnu. But that did not help.

The error I get is a sequence of errors in the link process like this one:

/usr/bin/ld: skipping incompatible /usr/lib/x86_64-linux-gnu/libpthread.so when searching for -lpthread

and here is a copy of my .pro file.

*#-------------------------------------------------

Project created by QtCreator 2014-10-14T11:06:28

#-------------------------------------------------

QT += core

QT -= gui

QMAKESPEC=linux-g++-32

QMAKE_CXXFLAGS += -std=c++0x
QMAKE_CXXFLAGS += -O0

INCLUDEPATH += /usr/share/jps-audioproc-third-party/boost/include
LIBS += -L/usr/share/jps-audioproc-third-party/boost/lib -lboost_program_options -lboost_system -lboost_thread
LIBS += -L/usr/lib/i386-linux-gnu -lpthread
LIBS -= -L/usr/lib/x86_64-linux-gnu

TARGET = Test2
CONFIG += console
CONFIG -= app_bundle

TEMPLATE = app

SOURCES += main.cpp*

]]>https://forum.qt.io/topic/47070/building-a-32bit-application-on-a-64bit-machineRSS for NodeMon, 04 May 2026 16:58:46 GMTWed, 15 Oct 2014 14:00:35 GMT60<![CDATA[Reply to Building a 32bit application on a 64bit machine. on Fri, 17 Oct 2014 12:26:19 GMT]]>I installed the 32 bit libraries in Ubuntu by running this:
@sudo apt-get install ia32-libs@

And yes I changed the makespec to 32 bit by putting this line in the *.pro file:
@QMAKESPEC=linux-g++-32@

But I also changed Projects->Build Settings->Build Steps->qmake->Additional arguments to:
@ -spec linux-g++-32@

]]>https://forum.qt.io/post/247976https://forum.qt.io/post/247976Fri, 17 Oct 2014 12:26:19 GMT<![CDATA[Reply to Building a 32bit application on a 64bit machine. on Wed, 15 Oct 2014 20:17:57 GMT]]>May I ask how you got 32bit Qt libraries on your 64bit machine. And have you checke the makespec system?

]]>https://forum.qt.io/post/247691https://forum.qt.io/post/247691Wed, 15 Oct 2014 20:17:57 GMT<![CDATA[Reply to Building a 32bit application on a 64bit machine. on Wed, 15 Oct 2014 16:33:44 GMT]]>This can't be the right way to fix this, but....
In Projects->Build Settings->Build Steps between the qmake and make steps I added a new step that does this:

sed -i 's|-L/usr/lib/x86_64-linux-gnu|-L/usr/lib/i386-linux-gnu|' Makefile

to change the location of the libraries. And it works now.

come-on-people...there must be a correct way.

]]>https://forum.qt.io/post/247668https://forum.qt.io/post/247668Wed, 15 Oct 2014 16:33:44 GMT<![CDATA[Reply to Building a 32bit application on a 64bit machine. on Wed, 15 Oct 2014 15:18:21 GMT]]>If I go into the make file and change:
-L/usr/lib/x86_64-linux-gnu
to
-L/usr/lib/i386-linux-gnu
in the LIBS line it all works!!

Of course next time qmake runs it is reverted.

But, I can't find out where qmake gets that variable.

]]>https://forum.qt.io/post/247656https://forum.qt.io/post/247656Wed, 15 Oct 2014 15:18:21 GMT<![CDATA[Reply to Building a 32bit application on a 64bit machine. on Wed, 15 Oct 2014 14:35:18 GMT]]>Hi,

I got around the problem by installing a 32-bit virtual machine on my 64-bit machine. If you find a better way, I'm very interested :).

]]>https://forum.qt.io/post/247650https://forum.qt.io/post/247650Wed, 15 Oct 2014 14:35:18 GMT