[R] Calling Fortran from C++

[cls59]

Giura Gauss wrote:
> 
> Hi,
> 
> can anybody point me to a package with C++ code that call Fortran
> subroutines?
> 
> I am trying to do the same thing but we scarce success.
> 
> Error in dyn.load("utils.so") :
>   unable to load shared library 'utils.so':
>   dlopen(utils.so, 6): Symbol not found: _robcovf
>   Referenced from: utils.so
>   Expected in: dynamic lookup
> 
> 
> 

It seems like you have a problem with function names which is a common
obstacle when interfacing C and Fortran. What usually happens is that a
trailing underscore gets added to fortran function names when they are
compiled. For example, consider a fortran subroutine declared as:

subroutine gaussQuad ( a, b, f1, f2 )

Since an underscore usually gets added and Fortran passes variables by
reference, the above subroutine would be seen by C as:

void gaussQuad_( a&, b&, f1&, f2& );

Furthermore, in C++ I think you h$ave to wrap the prototype in an extern
statement:

extern "C" { void gaussQuad_(a&, b&, f1&, f2& ); }

If you are running a unix system, you can check if your fortran function
names are receiving trailing underscores by running the nm utility on your
shared library. Ignore the leading underscores as they are expected by the C
compiler.

-Charlie




-----
Charlie Sharpsteen
Undergraduate
Environmental Resources Engineering
Humboldt State University
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