Experimental Physics and
Industrial Control System

"Mark S. Engbretson" <[email protected]> · Mon, 2 Feb 2015 14:28:45 -0600

DLL's are standalone entities which have resolved all their library
reverences at build time. The windows EPICS libs are already DLL's. ANYTHING
with the correct header files can talk to it - Pascal, Fortran, past
versions or future versions. All you have to do is find out if whatever code
that your building apps for can understand the DLL and link lib formats.
Grab a recent version for an APS Jenkin build and see what happens.
Microsoft is rather compatible with itself.

https://jenkins.aps.anl.gov/job/epics-base-3.14/
https://jenkins.aps.anl.gov/job/epics-base-3.15/

That being said - nothing keeps you from building those apps against a 15
year version of epics. You just don't get later features such as large
arrays.  Do you need anything that only exists in current versions?

-----Original Message-----
From: [email protected] [mailto:[email protected]]
On Behalf Of Johnson, Andrew N.
Sent: Monday, February 02, 2015 2:17 PM
To: J. Lewis Muir
Cc: EPICS Tech-Talk
Subject: Re: epicsRingPointer.h error C2664: 'delete' : cannot convert
parameter

Hi Lewis,

Microsoft's attitude to compatibility for C++ code is that you have to use
the same major compiler version to be able to link programs with separately
compiled libraries. C code does not have the same restrictions though, which
is why we can use gcc to build programs that link with the OS libraries, and
why Windows' APIs haven't been switched to C++ classes.

It sounds like you are building the vendor's code, which must be done with
VC6, but can add your own code to their program. I can suggest a few ways to
interface that with EPICS code built with a newer compiler: Use a socket or
COM API to to communicate between the two sides, or make the interface a DLL
with a C-only API as this should allow you to link with and call code from
the other compiler. A DLL would give you a closer and faster interface, but
might be more trouble to get working.

If all you need is to call the CA library it does provide the C-only API and
DLL that you need, so in this case you might be able to just copy the ca.dll
and com.dll files from another machine along with a few header files.

Hope this helps,

- Andrew

--
Sent from my iPad

> On Feb 2, 2015, at 1:21 PM, J. Lewis Muir <[email protected]> wrote:
> 
>> On 1/30/15 5:48 PM, Andrew Johnson wrote:
>> I don't think you'll be able to, MS Visual C++ 6 was released in 1998
>> (17 years ago, long before MS implemented standard C++) and it 
>> doesn't support all of the C++ constructs that we make use of in 
>> Base. In 2008 Jeff Hill explained that VC7 was too old to build
Base-3.14.9:
>>    http://www.aps.anl.gov/epics/tech-talk/2008/msg00078.php
>> 
>> Can't you upgrade the compiler?
> 
> Hi, Andrew.
> 
> Thanks for your reply.  I'm writing a library (that uses EPICS CA) 
> that I need to work with a vendor-supplied program.  Unfortunately, 
> I've been told by the vendor that the program will only build with 
> VC6, hence, in order to have the best chance of things working right, 
> I was planning to use the same compiler to build my library (and EPICS
Base).
> 
> So, to answer your question, upgrading the compiler is perhaps 
> possible, but I fear it might result in significant pain.
> 
> I'm not a Windows expert.  Is it possible to install, say, Visual 
> Studio
> 2010 *alongside* VC6 on Windows 7?  And if so, is it possible to 
> compile EPICS Base and my library as DLLs that the VC6 vendor-supplied 
> program can link against?
> 
> Thank you!
> 
> Lewis

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System