Qt programming tips

How to configure mkspec for paralel builds on Windows

Edit qmake.conf file in Qt\mkspecs\win32-msvcXXXX. Add -MP2 / -MP4 to the following defines:

QMAKE_CFLAGS_RELEASE    = -O2 -MD -MP4
QMAKE_CFLAGS_RELEASE_WITH_DEBUGINFO += -O2 -MD -Zi -MP4
QMAKE_CFLAGS_DEBUG      = -Zi -MDd -MP4

Mount error(12): Cannot allocate memory

Problem

When mounting some windows samba drives, “mount error(12)” error can occurred. Problem is in windows samba server settings. Full linux error message:

mount error(12): Cannot allocate memory
Refer to the mount.cifs(8) manual page (e.g.man mount.cifs)

and error message in windows event log:

Source: srv
Event ID: 2017
Level: Error
The server was unable to allocate from the system nonpaged pool because the server reached the configured limit for nonpaged pool allocations.

Solution

Update following registry:

HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\LargeSystemCache = 1
HKLM\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters\Size = 3

After you update these values, restart your computer.

More about this issue:

http://alan.lamielle.net

How to deploy Qt application on MacOs

Missing dylib libraries

If your application using some externals dynamic libraries (called .dylib in MacOs system), you have to provide all these libraries. The simplest way is to provide these libraries into the Application.app directory.

Find out which libraries are used

Qt provide really useful tool called “otool” which serves to lots of purpose. One of them is to detect which shared libraries are required by our application. For this purpose otool has parameter -L. The usage is following:

otool -L ./Test1.app/Contents/MacOS/Test1

Output could looks like this:

./Test1:
        libboost_iostreams.dylib (compatibility version 0.0.0, current version 0.0.0)
        libboost_filesystem.dylib (compatibility version 0.0.0, current version 0.0.0)
        libboost_system.dylib (compatibility version 0.0.0, current version 0.0.0)
        libboost_thread.dylib (compatibility version 0.0.0, current version 0.0.0)
        libboost_date_time.dylib (compatibility version 0.0.0, current version 0.0.0)
        libboost_regex.dylib (compatibility version 0.0.0, current version 0.0.0)
        /Users/dev/dev/SharedLibraries/libiconv/lib/libiconv.2.dylib (compatibility version 8.0.0, current version 8.0.0)
        /Users/dev/dev/ExternalLibraries/../SharedLibraries/libxml/lib/libxml2.2.dylib (compatibility version 10.0.0, current version 10.8.0)
        /Users/dev/dev/ExternalLibraries/../SharedLibraries/libxslt/lib/libxslt.1.dylib (compatibility version 3.0.0, current version 3.26.0)
        /Users/dev/dev/ExternalLibraries/../SharedLibraries/libxslt/lib/libexslt.0.dylib (compatibility version 9.0.0, current version 9.15.0)
        /Users/dev/dev/ExternalLibraries/yaml-cpp-0.2.5/build/libyaml-cpp.0.2.dylib (compatibility version 0.2.0, current version 0.2.5)
        QtGui.framework/Versions/4/QtGui (compatibility version 4.7.0, current version 4.7.0)
        QtCore.framework/Versions/4/QtCore (compatibility version 4.7.0, current version 4.7.0)
        /usr/lib/libstdc++.6.dylib (compatibility version 7.0.0, current version 7.9.0)
        /usr/lib/libgcc_s.1.dylib (compatibility version 1.0.0, current version 625.0.0)
        /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 125.2.0)

Output from “otool” is simmilar to linux tool “ldd”.

The Mac Deployment Tool

Because manual copying and configuring all shared libraries to our application could be difficult, Qt have deployment tool which do all work for us. Tool is called “macdeployqt” and can be found in /Developer/Tools/Qt/macdeployqt.

 /Developer/Tools/Qt/macdeployqt ./GeneratedFilesMacOs/Debug/Test1.app

Note: Every time when you call macdeployqt tool, project have to be build from scratch. But is sufficient when whole result directory is removed and linked again:

rm -rf ./GeneratedFilesMacOs/Debug/Test1.app/
make

g++ template method problem

Quick post about problem which I already solved, but think that could be handy for someone else.

I have following code:

template<class T>
struct Test
{
	T val;
	template <class T2>
	void DoSomething( T2 &obj )
	{
		obj.FindByType<int>();
	}
};

When compiling under Visual studio, everything is ok. But when try the same code snippet under g++, have following error:

test.cpp: In member function ‘void Test<T>::DoSomething(T2&)’:
test.cpp:48: error: expected primary-expression before ‘int’
test.cpp:48: error: expected ‘;’ before ‘int’

This is because compiler doesn’t known FindByType method, because T2 is templated argument. The solution which I found is in adding keyword template before FindByType method name. So updated source code will look like this:

template<class T>
struct Test
{
	T val;
	template <class T2>
	void DoSomething( T2 &obj )
	{
		obj.template FindByType<int>();
	}
};

After this update, code will be compiled correctly under both compilers.

Git tips

Show files status

git status #show all files
git statis -u -s #show untracked in short listing

Commit with message

git commit -m"text"

Recursive add files by mask to git

git add *.mask -A

Linux-recursive remove some files

find -iname '*mask' | xargs rm

How to create global .gitignore file

git config --global core.excludesfile /file-path/.gitignore-global

TENG – c++ templating engine

Project site: http://teng.sourceforge.net/?page=home

External project documentation: http://teng.olmik.net/

Latest TENG source code: http://teng.cvs.sourceforge.net/teng/ (Note: Source code referenced from main site isn’t latest! )

How to compile TENG on windows

Compilation under Windows is possible only using MinGW and with few modifications in TENG code (because there is few glitch which didn’t meet c++ standards). If you want more information or updated TENG version, please let me know.

How to install and configure git with ssh key

  • Download git client depends on your OS platform
  • Open your .ppk key in PuTTY Key generator and export key to OpenSSH key:
  • Content of this OpenSSH key store to file ~/.ssh/id_dsa (copy exported key to ~/.ssh folder and rename it to id_dsa)
  • Now change security permissions on this file to 400 (chmod 400 ~/.ssh/id_dsa)
  • Now cal ssh-add to load id_dsa key

And it’s done. Now you can use your git. For example clone some repository:

git clone ssh://[email protected]/~/repository/example.git

Automatic ssh-key loading during startup:

TODO

Linux tips

Here is few tricks for Linuch which we needed during our exploration of this system 😉

How to change executable flag for scripts recursively

find -iname '*.sh' | xargs chmod 777

How to configure shared library path

Add file atomix.conf to directory /etc/ld.so.conf.d. To this file enter following:

# atomix libraries
/home/USER_NAME/dev/SharedLibraries/libs

and then run

sudo ldconfig

External link: http://www.yolinux.com/TUTORIALS/LibraryArchives-StaticAndDynamic.html

VIM cheat sheet

External link: http://www.tuxfiles.org/linuxhelp/vimcheat.html

How to resize partition

Use gparted

sudo apt-get install gparted

Measure disk write speed

time sh -c "dd if=/dev/zero of=ddfile bs=8k count=100000 && sync"

List of usefull links for Visual Studio

How to customize autoexp.dat in Visual Studio 2005

http://mariusbancila.ro/blog/?p=26
http://www.virtualdub.org/blog/pivot/entry.php?id=120

Example visualizator for XString

String::CStringSmart<String::malloc_string_trait<String::string_trait<char> > >{
  preview([$c.m_pszData,s])
  stringview([$c.m_pszData,sb])
}

String::CStringSmart<String::malloc_string_trait<String::string_trait<wchar_t> > >{
  preview([$c.m_pszData,su])
  stringview([$c.m_pszData,sub])
}

How to configure STEP-INTO for Visual Studio 2005

External links:
Google group
www.cprogramming.com

http://blogs.msdn.com/b/andypennell/archive/2004/02/06/69004.aspx

Example how to setup ingoring step-into for MFC CString for VS2005

Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\VisualStudio\8.0\NativeDE\StepOver]
"\"20\""="\\scope:CString.*\\:\\:.*=NoStepInto"
"\"21\""="\\scope:CSmartObjPtr.*\\:\\:.*=NoStepInto"

Example how to setup ingoring step-into for MFC CString for VS2010 on 64bit system

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Microsoft\VisualStudio\10.0_Config\NativeDE\StepOver]
"22"=".*CStringSmart.*=NoStepInto"