Experimental Physics and
Industrial Control System

Compiling a Software driver - using gcc 3.4.2 and epics 3.14.6 - gives the following error:

 

../dev1394.c:178: warning: dereferencing type-punned pointer will break strict-aliasing rules

../dev1394.c:179: warning: dereferencing type-punned pointer will break strict-aliasing rules

../dev1394.c:180: warning: dereferencing type-punned pointer will break strict-aliasing rules

../dev1394.c:181: warning: dereferencing type-punned pointer will break strict-aliasing rules

../dev1394.c:182: warning: dereferencing type-punned pointer will break strict-aliasing rules

../dev1394.c:183: warning: dereferencing type-punned pointer will break strict-aliasing rules

 

Which is related to these lines in my code:

 

##################

epicsExportAddress(dset,devAi1394);

epicsExportAddress(dset,devAo1394);

epicsExportAddress(dset,devStringin1394);

epicsExportAddress(dset,devWaveform1394);

epicsExportAddress(dset,devMbbi1394);

epicsExportAddress(dset,devMbbo1394);

##################

 

Expanding the above macros shows no problem:

 

##################

extern dset *pvar_dset_devAi1394; dset *pvar_dset_devAi1394 = (dset *)&devAi1394;

extern dset *pvar_dset_devAo1394; dset *pvar_dset_devAo1394 = (dset *)&devAo1394;

extern dset *pvar_dset_devStringin1394; dset *pvar_dset_devStringin1394 = (dset *)&devStringin1394;

extern dset *pvar_dset_devWaveform1394; dset *pvar_dset_devWaveform1394 = (dset *)&devWaveform1394;

extern dset *pvar_dset_devMbbi1394; dset *pvar_dset_devMbbi1394 = (dset *)&devMbbi1394;

extern dset *pvar_dset_devMbbo1394; dset *pvar_dset_devMbbo1394 = (dset *)&devMbbo1394;

##################

 

When I compile using CFLAG= -fno-strict-aliasing, these warnings go away.

 

Any clues?

 

Cheers,

Ahed

 

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# Ahed Aladwan                            #

# SLS Controls / Paul Scherrer Institute  #

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