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[Rcpp-devel] Simple project segfaults

3 messages · Berry Kriesels, Dirk Eddelbuettel

#
Hi everybody,

Just now I was playing around with Rcpp in combination with Qt (I have 
found an excellent example on this). And decided to have a go(small 
dummyproject) at this myself.  Problem is that the application segfaults 
when I run it.

QtR.h
http://pastebin.com/AXT144SK

QtR.cpp
http://pastebin.com/JUUuCFN2

main.cpp
http://pastebin.com/yWUmDL17

mainwindow.cpp
http://pastebin.com/gE84ZtxH

I create an instance of my QtR class called qtr which creates an RInside 
session in the constructor. In my mainwindow.cpp I reference to my 
instance of qtr and then invoke the loadData method. In the loadData 
method I try to use 
m_R.parseEvalQ("cat("+fname_no_ext+"',file='outfile.txt',sep='\n')");

This results in a segfault.

However when I remove this line from the loadData method and add the 
m_R.parseEvalQ("cat("+fname_no_ext+"',file='outfile.txt',sep='\n')"); 
line to the constructor of QtR which is invoked in main.cpp it runs 
without trouble.

I probably am making a very obvious mistake. But I seem unable to see 
the issue at this point myself.

Berry

PS

I have used pastebin for readability, or would everybody prefer the code 
within the e-mail?




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8 days later
#
Hi again,

Later on I realised I had made some fundamental programming errors 
resulting in the mentioned segfault entirely not related to rcpp. (fixed 
now by the way).
I know that does not earn me many brownie points, so my apologies for my 
sloppy code. ;)

Thus far I can say that I still really like the rcpp package and keep 
thinking of new ways I could use it.

Berry
On 03/20/2013 11:15 PM, Berry Kriesels wrote:
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#
Berry,
On 29 March 2013 at 10:24, Berry Kriesels wrote:
| Hi again,
| 
| Later on I realised I had made some fundamental programming errors resulting in
| the mentioned segfault entirely not related to rcpp.  (fixed now by the way).
| I know that does not earn me many brownie points, so my apologies for my sloppy
| code. ;)

Very much appreciate that you report back that it all works now. If you do
have (public) samples somewhere, let us know. It is good to have more sample
of R + Qt apps.

| Thus far I can say that I still really like the rcpp package and keep thinking
| of new ways I could use it.

:)

Submitting patches is next, right?

Dirk