linking fortran subs

[Phil Cummins]

Hello,
 I am using octave-2.0.16 on a Redhat Linux system.
 I am trying to use mkoctave to compile a C++ program
which I can call from octave. The original program is 
a C program which calls some routines in a library compiled
from fortran. To call the frotran subroutines I use
pointer arguments, to conform with fortran's pass-by-reference,
and add an underscore after the subroutine names. (there are 
also some character string arguments). In any
case the C program works OK.
  To convert to a C++ program which I can call from octave,
I followed the famous "oregonator" example in converting
from C to C++. This also works fine, except when I try to
call the fortran subroutines. I find that if I have calls 
to these subroutines, there are undefined symbols - e.g.,
I call a fortran subroutine called "assign", which I
call from C as assign_(). But when I try this in the 
C++ program using mkoctave, I get error messages about
undefined symbols, as inicated below:
 
C program function prototype:
void assign_(int *, int *, char *, int);

C program function call statement:
     assign_(&unit_10,&mode,"ttim1.lis",9);

Error message after conversion to C++ and called from octave:
/home/cummins/src/seis/ttimes/octtst.oct: undefined symbol:
assign___FPiT0Pci

I looked in the liboctave/dMatrix.cc to see how lapack
routines are called, which lead me to try something like:

Function prototype:
extern "C"
{
  int F77_FCN (assign, ASSIGN) (int *, int *, char *, int);
  }

and

F77_FCN (assign, ASSIGN) (&unit_10,&mode,"ttim1.lis",9);

But this again gives me undefined symbols:

error: /home/cummins/src/seis/ttimes/octtst.oct: undefined symbol: s_rsue:
/home/cummins/src/seis/ttimes/octtst.oct `FSocttst__Fv'
error: /home/cummins/src/seis/ttimes/octtst.oct: undefined symbol: s_rsue:
/home/cummins/src/seis/ttimes/octtst.oct `_FSocttst__Fv'
error: unable to load functions from /home/cummins/src/seis/ttimes/octtst.oct

I guess it's pretty obvious that I have no clue about how 
to use this F77_FCN fortran interface. Can anyone please 
tell me, is this what I need to use? And if so, could someone
please point me to some documentation or comments in the 
octave source that might help me learn what to do?

Many thanks

-- Phil Cummins

---------------------------------------------------------------------
Phil R Cummins                              address@hidden
Frontier Research for Subduction Dynamics  tel(i/d):81/0-468-67-3393
JAMSTEC, 2-15 Natsushima-cho               fax(i/d):81/0-468-67-3409
Yokosuka 237-0061, Japan              



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