Raspberry Pi thread - pure virtual function called

PeterPan32

Hi,
I'm currently developing a big project under the Raspberry Pi 2 (with Qt Creator).
Yesterday I was dealing with threads. I got an annoying runtime error.
So I wrote a little example that shows my problem:

#include <iostream>
#include <thread>
using namespace std;

void hello_function()
{
    cout << "function hello"<<endl;
}

int main()
{
    cout << "1" << endl;
    thread t(hello_function);
    cout << "2" << endl;
    t.join();
    return 0;
}

output:

1
2
pure virtual method called
terminate called without an active exception

The error is caused by the thread. After some research I found out that this is a bug in gcc compiler:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62100
You'll also find out, that there is recommended to use "-mcpu=cortex-a8" as solution.
Can anyone explain me where to put this command? Possible to put this in qt's project file?

At last, some additional information:
Qt project file:

TEMPLATE = app
CONFIG += console
CONFIG -= app_bundle
CONFIG -= qt

CONFIG   += c++14
CONFIG += thread

SOURCES += main.cpp

include(deployment.pri)
qtcAddDeployment()

Some versions:
Qt Creator 3.2.1 based on Qt 5.3.2 (under Raspberry Pi 2)
g++ (Raspbian 4.9.2-10) 4.9.2

/etc/issue:
Raspbian GNU/Linux 8 \n \l

/proc/version:
Linux version 4.1.19-v7+ (dc4@dc4-XPS13-9333) (gcc version 4.9.3 (crosstool-NG crosstool-ng-1.22.0-88-g8460611) ) #858 SMP Tue Mar 15 15:56:00 GMT 2016

SGaist

Hi,

You can edit the qmake.conf file in the mkspecs/device/linux-rasp-pi2-g++ folder.

PeterPan32

Thank you for your help. But that didn't change anything.
I had a look at the makefile and I'm a bit confused:

CC            = /usr/bin/gcc
CXX           = /usr/bin/g++
DEFINES       = 
CFLAGS        = -pipe -marm -mfpu=vfp -mtune=arm1176jzf-s -march=armv6zk -mabi=aapcs-linux -mfloat-abi=hard -g -D_REENTRANT -Wall -W -fPIC $(DEFINES)
CXXFLAGS      = -pipe -marm -mfpu=vfp -mtune=arm1176jzf-s -march=armv6zk -mabi=aapcs-linux -mfloat-abi=hard -g -D_REENTRANT -std=c++1y -Wall -W -fPIC $(DEFINES)
INCPATH       = -I../threadtest -I. -I/usr/local/qt5/mkspecs/devices/linux-rasp-pi-g++
QMAKE         = /usr/local/qt5/bin/qmake
DEL_FILE      = rm -f
CHK_DIR_EXISTS= test -d
MKDIR         = mkdir -p
COPY          = cp -f
COPY_FILE     = cp -f
COPY_DIR      = cp -f -R
INSTALL_FILE  = install -m 644 -p
INSTALL_PROGRAM = install -m 755 -p
INSTALL_DIR   = cp -f -R
DEL_FILE      = rm -f
SYMLINK       = ln -f -s
DEL_DIR       = rmdir
MOVE          = mv -f
TAR           = tar -cf
COMPRESS      = gzip -9f
DISTNAME      = threadtest1.0.0
DISTDIR = /home/pi/build-threadtest-Qt_5_5_1_qt5-Debug/.tmp/threadtest1.0.0
LINK          = /usr/bin/g++
LFLAGS        = -Wl,-rpath-link,/opt/vc/lib -Wl,-rpath-link,/usr/lib/arm-linux-gnueabihf -Wl,-rpath-link,/lib/arm-linux-gnueabihf -mfloat-abi=hard
LIBS          = $(SUBLIBS) -lpthread 
AR            = /usr/bin/ar cqs
RANLIB        = 
SED           = sed
STRIP         = /usr/bin/strip
...

Should the compiler flag -march=armv6zk not be something like armv7 ?
I also tried to add -mcpu=cortex-a8 manually, but the compiler reacts with a warning:
warning: switch -mcpu=cortex-a8 conflicts with -march=armv6zk switch

I think I have a bad setting. Obviously the makefile does not fit to the qmake.conf:

# qmake configuration for the Raspberry Pi 2

include(../common/linux_device_pre.conf)

QMAKE_LFLAGS           += -Wl,-rpath-link,$$[QT_SYSROOT]/opt/vc/lib

QMAKE_LIBDIR_OPENGL_ES2 = $$[QT_SYSROOT]/opt/vc/lib
QMAKE_LIBDIR_EGL        = $$QMAKE_LIBDIR_OPENGL_ES2

QMAKE_INCDIR_EGL        = $$[QT_SYSROOT]/opt/vc/include \
                          $$[QT_SYSROOT]/opt/vc/include/interface/vcos/pthreads \
                          $$[QT_SYSROOT]/opt/vc/include/interface/vmcs_host/linux
QMAKE_INCDIR_OPENGL_ES2 = $${QMAKE_INCDIR_EGL}

QMAKE_LIBS_EGL          = -lEGL -lGLESv2
QMAKE_CFLAGS += -march=armv7-a -marm -mthumb-interwork -mfpu=neon-vfpv4 -mtune=cortex-a7 -mabi=aapcs-linux
QMAKE_CXXFLAGS          = $$QMAKE_CFLAGS

DISTRO_OPTS += hard-float

# Preferred eglfs backend
EGLFS_DEVICE_INTEGRATION = eglfs_brcm

include(../common/linux_arm_device_post.conf)

load(qt_config)

Regards

SGaist

Is it me or the pasted qmake.conf doesn't contain cortex-a8 ?

onek24

@SGaist said:

mkspecs/device/linux-rasp-pi2-g++

Shouldn't it maybe be mkspecs/device/linux-rasp-pi-g++ (without the 2)?
In his makefile there is this line:

INCPATH       = -I../threadtest -I. -I/usr/local/qt5/mkspecs/devices/linux-rasp-pi-g++