Summary of answers and a new question
buteau at bali.saclay.cea.fr
Tue Dec 16 15:40:12 CST 1997
Thank you to all the people who answered me !!!
Nexus list seems to be an active list !!!
First the SUMMARY:
Question : >
> I read the Nexus www server and I have now the following questions:
> 1) Nexus defines various Groups to store datas like NXsample for instance
> I understood that NXSample is a NX_Group (not a NexusDataSet) but it seems to
have a lot of attributes (name, chemical formula, electrical fiels , and so on).
> I also understood that Nexus API provides functions to add attributes to data set
only (and not to groups even if HDF allows to add Vgroup attributes ).
> So my question is how should I add this kind of attributes to groups like
Answer: Nexus uses only the underlying HDF Vgroup and SDS:
Moreover Nexus doesn't use Vgroup attributes.
So all the attributes of a Vgroup (as for instance the attribute temperature of the
are declared as SDS.
The code to do this one operation, assuming that an NXentry group is
already open, would be
/* Open NXsample group within NXentry group */
NXmakegroup (file_id, "Sample", "NXsample");
NXopengroup (file_id, "Sample", "NXsample");
/* Output temperature */
NXmakedata (file_id, "temperature", NX_FLOAT32, 1, 1);
NXopendata (file_id, "temperature")
NXputdata (file_id, temperature);
NXputattr (file_id, "units", "K", 1, NX_CHAR);
/* Close NXsample group and close file */
> 2) a related question is : may somebody send me a real code example which fills
> than the small example given in the API document. (even if I cannot directly
compile this example , what I want is to see how people effectivly use the Nexus
Thanks to all the contributors who sent real code wich helps a lot .
> 3) And a question related to HDF and not Nexus but maybe someone in this list
may have solved the problem: for PC platforms , HDF gives statically linked
librairies for the MS compiler. Unfortunatly I use the Borland compiler which
cannot link with these libs . Has anybody compiled the HDF librairies for BC++ 5.X
Compiling these librairies on a PC platform is really painful. I tried during a
while but I gave up because technical problems
Thanks to FORTNER Research (http://www.fortner.com) (which seems to be very active
in the HDF market) I get their HDF DLLs and the linking
between Borland and DLL is quite easy to do .
Now the last question about the NXLog Type:
I now understand how to write data whose type is NX_CHAR , NX_FLOAT32, ,
but how should I write a data whose type is NXlog ?
I need further details please .
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