ClickHouse/contrib/libpoco/doc/99200-WinCEPlatformNotes.page

POCO C++ Libraries Windows CE Platform Notes
AAAIntroduction

!!!Introduction

Starting with release 1.4.0 the POCO C++ Libraries can be used on 
Windows CE 6. Project files for Visual Studio 2008 are provided that
support static and shared debug and release builds.

The port should work for Windows CE 5 as well, however, this has not been tested.


!!!Changing The Target In The Project Files

The project files contain build configurations for the "Digi JumpStart (ARMV4I)"
target. To use another target, the Visual Studio project and solution files
must be changed accordingly. Note that the project files cannot be opened 
by Visual Studio unless the target referenced in the project and solution files is available.
To change the project and solution files for your platform, replace
all occurrences of the string "Digi JumpStart (ARMV4I)" with the name
of your platform (e.g. "Windows Mobile 6 Professional SDK (ARMV4I)").
This is best done with a text editor that supports global search/replace
across an entire directory tree (solution and project files are plain text/xml
files, so there's no risk breaking something).


!!!Restrictions

!!Poco::Environment

Windows CE does not support environment variables. 
Therefore, Poco::Environment::get() and Poco::Environment::has() only support the
following hardcoded "pseudo" environment variables:
  * TEMP
  * TMP
  * HOMEPATH
  * COMPUTERNAME
  * OS
  * NUMBER_OF_PROCESSORS
  * PROCESSOR_ARCHITECTURE
  
Poco::Environment::set() always throws a Poco::NotImplementedException.


!!Date/Time Support

Some date/time features are implemented with the help of [[http://wcelibcex.sourceforge.net/ WCELIBCEX]].
The library is statically included in the Foundation library to simplify the build process. 
However, it is also possible to use WCELIBCEX as a separate library if the Foundation project file is modified accordingly
(by removing or excluding from build the WCELIBCEX folder and modifying the header file search path accordingly).
The following functions from WCELIBCEX are used:
  * wceex_time()
  * wceex_localtime()
  * wceex_mktime()
  
It should also be possible to use wcecompat instead of WCELIBCEX, as this library provides 
similar features. In this case, the calls to the wceex_* functions need to be replaced with
the wcecompat counterparts. The affected files are Random.cpp, LocalDateTime.cpp,
Timezone_WINCE.cpp and ThreadPool.cpp.

To obtain the current date and time with millisecond resolution,
the hack described in <http://community.opennetcf.com/articles/cf/archive/2007/11/20/getting-a-millisecond-resolution-datetime-under-windows-ce.aspx>
is used. This means there will be a one second delay when starting up
the application.


!!Poco::Path

Poco::Path::listRoots() returns the root directory ("\"), as well as all mounted storage devices 
(e.g., "\Hard Disk"), even if they are also present in the root directory.

Poco::Path::current() and Poco::Path::home() always return the root directory.


!!Poco::RWLock

In the reader/writer lock implementation for Windows CE, writers always take precedence over readers.


!!Poco::Process

Launching a process with pipes for redirecting input/output is not supported.


!!Poco::Util::ServerApplication

Poco::Util::ServerApplication::waitForTerminationRequest(): CTRL-C does not work to shut down the application as
it's not supported by the Windows CE console. The pkill utility supplied as part of the Util library
samples can be used to terminate a process from the command line.


!!Crypto and NetSSL

Crypto and NetSSL_OpenSSL have not been tested yet. Project files are there, but they might need some adaptions depending on 
how OpenSSL has been built for the Windows CE target.


!!Data

Only the SQLite backend is currently supported.

The SQLite engine in Data/SQLite is built without localtime support (SQLITE_OMIT_LOCALTIME) due to localtime_s() not being
available on Windows CE.


!!Raw Sockets in Net

The test cases involving raw sockets will fail unless the testsuite is ran as a privileged (signed) application.
These are RawSocketTest::testEchoIPv4(), RawSocketTest::testSendToReceiveFromIPv4() and ICMPClientTest::testPing().


!!!Build Notes

Optimization settings should be set as follows for release builds 
(<*Properties > Configuration Properties > C/C++ > Optimization*>):
  * Optimization: Custom
  * Inline Function Expansion: Default
  * Enable Intrinsic Functions: Yes (/Oi)
  * Floating-Point Consistency: Default Consistency
  * Favor Size or Speed: Favor Fast Code (/Ot)
  * Whole Program Optimization: No

Other settings may or may not produce working programs. 
Specifically, setting <*Optimization*> to <*Maximize Speed (/O2)*> will result in failures in the 
test suite for Foundation Events due to a compiler optimizer bug.

For shared/DLL builds, the /FORCE:MULTIPLE option is passed to the linker. This is
to avoid a problem with iostream classes and their methods (template instantiations), 
which for some unknown reason (possibly bug) will be exported by the Foundation library 
(and others) and thus cause multiply defined symbol errors.

The reference system used for testing is a Digi ConnectCore 9P 9360 running Windows CE 6.0.