RE: [Dev-C++] Mixed Language Programming w/Dev-Cpp

Hi all,
I suggest we are missing the point of the original question.

The original question was about mixed-language programming.
 i.e. a compiler that is capable of compiling a single program, one part
of which is written in C and another oart in FORTRAN. GCC IS a mixed
compiler.

What you seem to  be dealing with below is CONVERTING a program written in
FORTRAN to an equivalent C/C++ program.

 Converting a FORTRAN program is difficult because of the fundamental
differences in the way FARTRAN and C/C++ stores multi-dimentional arrays,
the way parameters are passed to functions, and the way arrays are indexed
(C arrays start with index zero, FORTRAN starts with 1). You have to
re-write a program to convert it or use a program like 'f2C' (which in my
experience works poorly)

A MIXED compiler (if working correctly) is well-aware of the FORTRAN vs
C/C++ differences and should compile object code for mixed programs
correctly. The only thing that one has to learn is how to place, in the
source code, a compiler instruction or 'switch' that tells the gcc
compiler to begin and end the processing FORTRAN source code statements.
 I not sure how to do this with gcc.

 
--- Per Westermark <pw...@ia...> wrote:
> When you have declared
> double a[10][10]
> it is quite important to know in which order the individual values are
> stored in memory, when trying to interface between two languages.
> 
> If your C program does a[x][y] and your Fortran program has do do
> a[z][y] to reach the same entry. No problem when you have all three
> index variables available.
> 
> However, when you take a pointer to a an entry inside the array, the
> operation might be seen as a projection down to an array with fewer
> dimensions. Obviously, if the entry order in memory has been transposed,
> the such a projection will fail misserably when switching languages. The
> 
> sender thought it sent a row, but the receiver got a column.
> 
> When people originally started to push for the C language, the above
> problem gave rise to a related problem. When referencing large memory
> structures, it is important to assure that the code uses locality of
> reference and doesn't jump around everywhere in the data. Large linear
> packages are always implemented so that they process entries in the same
> order that they are stored in memory. When converting such an algorithm
> -
> might be thousands uppon thousands of lines of code - it isn't s easy to
> just try and adjust for row/column switches. The result is that a C
> translation of a Fortran algorithm might loose 10-30% or maybe more of
> the
> speed when the same Fortran algorithm was run.
> The mathematical world decided that C was a slower language :-)
> Nowadays,
> there are a lot of good algorithms originally written for C, so this
> issue
> shouldn't be a problem anymore. But still, there are some billion
> Fortran lines of optimized and very advanced mathematics algorithms out
> there.
> 
> /Per W
> 
> On Wed, 30 Oct 2002, Marc Heiligers wrote:
> 
> > To Ioannis,
> > 
> > Funny thing is I was reading an old Turbo C reference guide I have
> lying
> > around that mentioned linking Turbo C and Turbo Fortran (was it called
> > that?). Borland seemed to very proud of this cross language linking.
> There
> > are some difficulties with function name decoration and what-not that
> you
> > need to be aware of. I can't quite recall what they were, but I'll try
> to
> > remember to take a look this evening.
> > 
> > I'm not sure if the same advice will apply here since it is clearly
> > different compilers, but it may give you an idea. I'd still look on
> the net
> > for info specific to the compilers you want to use.
> > 
> > To Per,
> > Is there anything you don't know anything about? (LOL).
> > 
> > I don't recall if the above mentioned book mentioned any difficulties
> with
> > multi-dimensional arrays. Besides, as far as I'm aware, C uses arrays
> of
> > arrays and not multi-dimensional arrays, so would the trick not be to
> set
> > your arrays up in the same way that Fortran does?
> > 
> > _____________________________
> > Marc Heiligers
> > 
> > 
> > -----Original Message-----
> > From: Per Westermark [mailto:pw...@ia...] 
> > Sent: 30 October 2002 11:40 AM
> > To: Ioannis Vranos
> > Cc: Dev-C++ Mailing List
> > Subject: RE: [Dev-C++] Mixed Language Programming w/Dev-Cpp
> > 
> > 
> > I think there might be acoule of gotchas more to think about.
> > 
> > Doesn't fortran have the reversed row/column order for
> multi-dimensional
> > arrays?
> > 
> > Anyway, I assume that there already exists excellent FAQ documents for
> this
> > kind of problems.
> > 
> > /Per W
> > 
> > On Wed, 30 Oct 2002, Ioannis Vranos wrote:
> > 
> > > > -----Original Message-----
> > > > From: dev...@li...
> > > > [mailto:dev...@li...] On Behalf 
> > > > Of Scott Williams
> > > > Sent: Tuesday, October 29, 2002 10:34 PM
> > > > To: Dev-Cpp-Users@Lists. Sourceforge. Net
> > > > Subject: [Dev-C++] Mixed Language Programming w/Dev-Cpp
> > > > 
> > > > 
> > > > Hi,
> > > > 
> > > > Wondering if anyone has experience with mixed language programming
> 
> > > > and whether it can be done with Dev-Cpp?
> > > > 
> > > > In particular, I'm writing a mathematical simulation in C
> > > > (using Dev-Cpp)
> > > > and would like to make using of some existing numerical 
> > > > routines in Fortran.
> > > > My C knowledge is necessity-based self-taught and so limited; 
> > > > don't know
> > > > anything about Fortran.  Neither do I know much about using
> > > > compilers/linkers/etc in command line mode (which is why I 
> > > > use Dev-Cpp--I
> > > > let it worry about that stuff).
> > > > 
> > > > Still, I know that built-in to the gcc interface is the g77
> > > > compiler so
> > > > there must be a way to compile the fortran source to an 
> > > > object with g77 and
> > > > then link to & call the routines from C.  Could it be as 
> > > > simple as added
> > > > fortran source files to my Dev-Cpp project?  If so, any 
> > > > thoughts on how to
> > > > prototype the Fortran functions & subfunctions to make them 
> > > > accessible to
> > > > the C calling routines?
> > > 
> > > 
> > > Well if you download the whole MINGW distribution it contains a 
> > > Fortran compiler. In theory as i can think of it, if you compile
> your 
> > > fortran source code files to .o files and use C-style declarations
> of 
> > > those functions in your C source code, you should be able to use
> them.
> > > 
> > > 
> > > Ioannis
> > > 
> > > * Ioannis Vranos
> > > * Programming pages: http://www.noicys.freeurl.com
> > > * Alternative URL: http://run.to/noicys
> > > 
> > > 
> > > 
> > > 
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> > 
> > 
> > 
> 
> 
> 
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