Experimental Physics and
Industrial Control System

Hi Eric,

On Monday, July 25, 2011 12:54:28 Eric Norum wrote:
> Downloaded and installed OS X Lion and the latest version of Xcode on my
> laptop machine.  Attempting to build EPICS results in:
> /usr/bin/c++ -c -DUNIX  -Ddarwin     -O3 -g   -Wall      -arch i386   
> -fno-common -fPIC -MMD -I. -I../O.Common -I. -I..
> -I../../../include/os/Darwin -I../../../include       -I/opt/local/include
> -I/sw/include  ../udpiiu.cpp ../udpiiu.cpp:1391: error: generic thunk code
> fails for method 'virtual int
> udpiiu::printFormated(epicsGuard<epicsMutex>&, const char*, ...)' which
> uses '...'

We've seen this twice now at APS with GCC 4.1.2 built for both the Xilinx and 
Altera FPGA-based CPUs.  I managed to narrow the code down to to one simple 
file, attached here, which contains valid C++ code but is using some rather 
unusual combination of operations (mixing the use of ... with double 
inheritance) that requires some thunking code that is often not developed for 
new CPUs.  It's basically that whoever wrote the CPU support didn't finish the 
job, and EPICS is the first code to notice.

- Andrew (from England, on holiday)

/* Compiling this file with the microblaze version of g++ generates
 * the generic thunk error:
 *
 * rhel6% microblazeel-unknown-linux-gnu-g++ -c broken.cpp
 * broken.cpp:32: error: generic thunk code fails for method
 *     'virtual void C::f(const char*, ...)' which uses '...'
 *
 */

class A {
public:
    virtual ~A () = 0;
};

class B {
public:
    virtual ~B () = 0;
    virtual void f (const char *, ...) = 0;
};

class C:
    public A,
    public B {
public:
    virtual ~C ();

    void f (const char *, ...);
};

void C::f (const char * p, ...)
{
    // This is line 32
}

Replies:

RE: EPICS on OS X Lion -- C++ problem Jeff Hill

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EPICS on OS X Lion -- C++ problem Eric Norum

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