Experimental Physics and
Industrial Control System

Mark Rivers <[email protected]> · Tue, 21 Mar 2017 12:31:43 +0000

Hi Ralph,

I don't use epicsExportAddress very much.  But I just did a search of all of synApps, including areaDetector, and found this:

corvette:~/devel>find . -name '*.cpp' -exec grep -H epicsExportAddress {} \;
./areaDetector-2-6/ADCore/ADApp/ADSrc/NDArrayPool.cpp:extern "C" {epicsExportAddress(int, eraseNDAttributes);}
./motor-6-9/motorApp/NPointSrc/C300MotorDriver.cpp:extern "C" {epicsExportAddress(int, C300Tolerance);}
./motor-6-9/motorApp/OmsAsynSrc/omsMAXv.cpp:extern "C" {epicsExportAddress(int, motorMAXvdebug);}
./motor-6-9/motorApp/OmsAsynSrc/omsMAXvEncFunc.cpp:extern "C" {epicsExportAddress(int, motorMAXvEncFuncdebug);}
./motor-6-9/motorApp/OmsAsynSrc/omsMAXnet.cpp:extern "C" {epicsExportAddress(int, motorMAXnetdebug);}
./motor-6-9/motorApp/OmsAsynSrc/omsBaseController.cpp:extern "C" {epicsExportAddress(int, motorOMSBASEdebug);}

So all instances are indeed wrapped in extern "C".

A search of base 3.14.12.5, 3.15.5, and EPICS V4 4.6.0 finds no occurrences of epicsExportAddress in .cpp files.

Mark

________________________________
From: [email protected] [[email protected]] on behalf of Ralph Lange [[email protected]]
Sent: Tuesday, March 21, 2017 7:16 AM
To: EPICS Core Talk
Subject: epicsExport.h on Windows

Dear Core-Talkers,

For a device support partly written in C++, we have been getting a pull request for Windows builds that adds extern "C" declarations around EPICS exports, e.g.

-epicsExportAddress(double, connectInterval);
+extern "C" {
+    epicsExportAddress(double, connectInterval);
+}

with the comment

I am afraid that the extern statements in epicsExport.h are ignored by VS compiler when expanding the epicsRegisterFunction macro. Therefore they need to be repeated here otherwise we get a linking failure when building test IOC.

As my Windows experience is very limited - is there a better way to handle that?

Thanks,
~Ralph

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System