Start of touch calibration

Technical Support
1

Hello,

I have to start touch calibration from within my application. As you describe on the page Touch Screen Calibration (WinCE) | Toradex Developer Center I just have to call the TouchCalibrate() function.
Unfortunately after I added the call to this function, I get linker errors which tell me that the function ist not defined. I read the MSDN page TouchCalibrate (Windows Embedded CE 6.0) | Microsoft Learn but I cannot link against the library mentioned there.

Please tell me what I have to do to start touch calibration from my application.

Best regards,
Florian Pfanner

2

@fox
Please tell us which operating system, BSP version and module you are using so we can quickly test this. Thanks.

3

Please, in addition to what Roman asked, please copy also the error message you get when trying to build your code.

4

Hello Valter,

I created a minimal example, see files attached. The error message shown in Visual Studio:

1>------ Erstellen gestartet: Projekt: TouchCalibrationTest, Konfiguration: Debug Colibri600 (ARMV4I) ------
1>Verknüpfen…
1>main.obj : error LNK2019: Verweis auf nicht aufgelöstes externes Symbol "“int cdecl TouchCalibrate(void)" (?TouchCalibrate@@YAHXZ)" in Funktion “main”.
1>corelibc.lib(mainwcrt.obj) : error LNK2019: Verweis auf nicht aufgelöstes externes Symbol “wmain” in Funktion "“void cdecl mainCRTStartupHelper(struct HINSTANCE *,unsigned short const *)” (?mainCRTStartupHelper@@YAXPAUHINSTANCE@@PBG@Z)”.
1>Colibri600 (ARMV4I)\Debug/TouchCalibrationTest.exe : fatal error LNK1120: 2 nicht aufgelöste externe Verweise.
1>Das Buildprotokoll wurde unter “file://d:\Projekte\33134_Hematech\TouchCalibrationTest\TouchCalibrationTest\Colibri600 (ARMV4I)\Debug\BuildLog.htm” gespeichert.
1>TouchCalibrationTest - 3 Fehler, 0 Warnung(en)
========== Erstellen: 0 erfolgreich, Fehler bei 1, 0 aktuell, 0 übersprungen ==========

link text

5

You should declare TouchCalibrate as extern “C”:

extern “C” BOOL WINAPI TouchCalibrate(void);

All Windows APIs are exported with an undecorated name (since they are C not C++), and if you declare them in a C++ file (just the cpp extension is enough to make it C++) you’ve to specify the correct linkage.

6

Excactly this was the problem!

Thank you very much for your valuable help.
Best regards,
Florian

7

Hello Roman,

tank you for your quick answer.

I work with a Colibri Tegra T20 with bootloader version 1.2 and image version 1.2 (CE7.0). For development Visual Studio 2008 is used (without platform builder).

Many thanks in advance,
Florian