Development with Qt for Windows CE
- 1. Development with Qt for Windows CE 10/11/09
- 2. Agenda • Introduction to Windows CE • How to build Qt for Windows CE • Windows CE 5 memory model • Ways to more memory • Demonstration
- 3. What is Windows CE? • OS for embedded devices • not derived from desktop Windows • monolithic kernel • highly configurable using Platform Builder • runs on x86, ARM, SH4 and MIPS 3
- 4. The world of Windows CE • Windows CE 5.2 – Windows mobile 5, 6, 6.1, 6.5 • SmartPhone (standard) • PocketPC (classic / professional) • Windows CE 6.0 R2 – Microsoft Auto – Windows mobile 7? 4
- 5. Desktop Windows vs. Windows CE • UTF16 string representation • No NTFS support → no file security model • No file drives • No current directory • Only 32 processes • Only 32 MB memory per process (CE < 6) 5
- 6. Desktop Windows vs. Windows CE • Number of threads limited to system resources – no more free memory → no more threads • API is a Win32 API subset – no *A functions – no asynchronous file I/O or network – incomplete standard C libs 6
- 7. Desktop Windows vs. Windows CE • Situation gets better with Windows CE 6 – Up to 1 GB process memory – More than 32K processes – Improved system call performance – New product name: Windows embedded CE 7
- 8. What do you need for development? • Visual Studio 2005 Standard or Visual Studio 2008 Professional • Windows CE SDK for your device • Qt for Windows CE from qt.nokia.com • Perl for using out-of-source builds • Qt Visual Studio Add-in from qt.nokia.com 8
- 9. Development work flow • Prototype on Desktop Windows • Switch to a Windows CE Qt build • Build, deploy and run – Not everybody in the team needs a Windows CE development environment. 9
- 10. How to build Qt for Windows CE? • Use shadow builds. C:Qt4.6.0qtsource win32 wincewm60professional wince50standard-x86 10
- 11. How to build Qt for Windows CE? Open a Visual Studio command prompt. Add C:Qt4.6.0wincewm60professionalbin to PATH. cd C:Qt4.6.0wincewm60professional .qtsourcesconfigure -xplatform wincewm60professional-msvc2008 -signature mysignature.pfx Creates Qt configuration and builds the host tools: • qmake, moc, uic, rcc • setcepaths / checksdk • cetest (if Remote API is in INCLUDE, LIBS) 11
- 12. How to build Qt for Windows CE? ...only two steps left... setcepaths wincewm60professional-msvc2008 nmake 12
- 13. Qt DLL sizes Library sizes of Qt 4.5.2 on Windows mobile 6 professional: Qt library Size in MB QtCore4.dll 1.67 MB QtGui4.dll 5.67 MB QtNetwork4.dll 0.53 MB QtWebKit4.dll 6.86 MB qjpeg4.dll 0.12 MB sum 14.85 MB 13
- 14. The Windows CE 5.0 memory model Slot 63 Resource only DLLs • only 32 MB per slot • Application stack & heap grow large memory area from slot's bottom Slot 32 Process 32 • DLLs are loaded into process slots top-down ... • DLLs are guaranteed to have Slot 3 the same address in every slot Process 2 Slot 2 Process 1 Slot 1 bundled DLLs Slot 0 current process 14
- 15. The Windows CE 5.0 memory model Bundled DLLs Load address for new DLLs 15
- 16. The Windows CE 5.0 memory model Qt DLLs Stack & heap 16
- 17. Ways to more Virtual Memory • Reduce the DLL size • Use static linking • Load small DLLs first • Switch to Windows mobile 6.1 17
- 18. Reducing Qt DLL sizes • Exclude the features you don't need • “feature” = set of classes (e.g. GraphicsView) • define QT_NO_FEATURENAME configure -D QT_NO_FEATURENAME • add this define to your application .pro file DEFINES += QT_NO_FEATURENAME • Tedious stuff! Is there no easier way to do this? 18
- 19. Reducing Qt DLL sizes using qconfig
- 20. Reducing Qt DLL sizes using qconfig In your desktop Windows Qt build directory: md toolsqconfig cd toolsqconfig qmake ......toolsqconfigqconfig.pro nmake release releaseqconfig.exe 20
- 21. Reducing Qt DLL sizes using qconfig Good candiates for exclusion: • Standard dialogs (color, font, input, wizard, …) • Convenience widgets (QCalendarWidget, ...) • Clipboard, drag and drop, shortcuts • QtConcurrent, FTP, QSystemTrayIcon • GraphicsView for QWidget only applications • MDI 21
- 22. Reducing Qt DLL sizes using qconfig • Open the features description file in srccorelibglobalqfeatures.txt • Unselect unwanted features • Save the result in srccorelibglobalqconfig-myfeatures.h • Reconfigure Qt configure -qconfig myfeatures ... 22
- 23. Reducing Qt DLL sizes 2.43 minimal 1.42 4.18 QtCore small 1.67 QtGui 5.67 standard 1.67 0 1 2 3 4 5 6 23
- 24. Accessing the Large Memory Area • just 32 MB? Are you serious? • there's more behind slot 32 • use memory mapped files • use the VirtualAlloc API 24
- 25. Accessing the Large Memory Area Using memory mapped files: • acquire memory at 64 K boundaries QFile memfile("myfile.bin"); memfile.open(QIODevice::ReadWrite); memfile.resize(1024*1024*2); uchar* buf = memfile.map(0, 1024*1024*2); ... memfile.unmap(buf); memfile.remove(); 25
- 26. Accessing the Large Memory Area Using VirtualAlloc: • Reserve memory at 64 K boundaries or commit reserved memory at 4 K boundaries void* ptrBase = VirtualAlloc(0, dwSize, MEM_RESERVE, PAGE_NOACCESS); buffer = VirtualAlloc(ptrBase, dwSize, MEM_COMMIT, PAGE_READWRITE); ... VirtualFree(ptr, dwSize, MEM_DECOMMIT); VirtualFree(ptr, 0, MEM_RELEASE); 26
- 27. Demonstration