Re: [O] Details of compling and running C++ code from Org-mode?

[Michael Hannon]

Nice.  Very interesting and informative.  Thanks, Eric.

-- Mike



----- Original Message -----
> From: Eric Schulte <address@hidden>
> To: Michael Hannon <address@hidden>
> Cc: Org-Mode List <address@hidden>
> Sent: Friday, November 18, 2011 11:39 AM
> Subject: Re: [O] Details of compling and running C++ code from Org-mode?
> 
> Hi Michael,
> 
> Michael Hannon <address@hidden> writes:
> 
>>  Greetings.  I'm curious about the process of executing a program that 
> is
>>  compiled from a source block in Org-mode.
>> 
>>  Some background: I was playing with some C++ code (a slight generalization 
> of
>>  some code I found in a book).  I wanted to use the "assign" 
> method to
>>  initialize a vector, as:
>> 
>>      vector<int> testVec(5, 0);
>>      testVec.assign({2, 4, 6, 8, 10});
>> 
>>  It turns out that to do this one has to tell g++ (in my case) to use the
>>  latest version of the C++ standard.  I discovered that I could do this via:
>> 
>>      (setq org-babel-C++-compiler "g++ -std=c++0x")
>> 
> 
> You could also use the :flags header argument (:flags "-std=c++0x") to
> pass this flag to g++.
> 
>> 
>>  This got me to wondering if there were any similar hooks that relate to
>>  running the program once it's compiled.  I looked through the list of
>>  org-babel* variables, but didn't find anything obvious.
>> 
>>  So what does happen when I hit C-c C-c in, say, a cpp source-code block?  
> The
>>  contents of the file are evidently written to a temporary file, after which
>>  the command specified by org-babel-C++-compiler is run on that file.  The
>>  results of the compilation are stuck some place -- another temporary file, 
> I
>>  suppose.  Then the second, executable file is run and the results
>>  collected.
> 
> Thanks for asking this question, and sorry it took so long to respond.
> I've placed an annotated copy of the relevant code up at [1] which
> should explain the evaluation process for c/c++ code.  In many cases
> browsing the relevant org-babel-execute:* function for your language is
> the best way to discover what flags are available.
> 
>> 
>>  What command runs the file?
> 
> The file itself is called directly.
> 
>>    Is there any control from Org-mode over this second stage of the
>>  process?
> 
> Yes, the :cmdline header argument may be used to pass values to the
> executing file.
> 
> Best -- Eric
> 
>> 
>>  Thanks,
>> 
>>  -- Mike
>> 
> 
> 
> Footnotes: 
> [1]  http://cs.unm.edu/~eschulte/data/babel-c-execution.html
>      http://cs.unm.edu/~eschulte/data/babel-c-execution.org
> 
> -- 
> Eric Schulte
> http://cs.unm.edu/~eschulte/
>