How To Get To Fortran Common Variables Within a C Code

[Christopher M. Lusardi]

Hi,

I know about the convention of appending "_" to c routine names, but
how do I access Fortran global variables in c?

Thank you,
Christopher Lusardi

 

[Mark A. Odell]

(e-mail address removed) (Christopher M. Lusardi) wrote in

I know about the convention of appending "_" to c routine names, but
how do I access Fortran global variables in c?

Sadly, the C language does not specify how to do this (e.g. no help here).

 

[Derk Gwen]

# I know about the convention of appending "_" to c routine names, but
# how do I access Fortran global variables in c?

You need to verify the details with your compiler vendors, but the
general idea is that
common /abc/ x,y,z
real x
integer y
complex z
corresponds to the global variable declaration
struct {
double x;
int y;
struct {double re,im;} z;
} abc;
with details varying with the system and compilers.

 

[E. Robert Tisdale]

I know about the convention
of appending "_" to [Fortran] routine names,
but how do I access Fortran global variables [from] C?

Fortran 77 does not support "global" variables.

> cat file.f

program main
common/structure/i, x
integer i
real x
end

> g77 -c file.f
> nm file.o

00000000 T MAIN__
U s_stop
00000008 C structure_

The common block named structure is identified by the symbol structure_.
In your C program, define a global variable

struct {
int i;
float x;
} structure_;

so that you can reference the data members of the common block

structure_.i

and

structure_.x

 

[CBFalconer]

I know about the convention
of appending "_" to [Fortran] routine names,
but how do I access Fortran global variables [from] C?

Fortran 77 does not support "global" variables.

cat file.f

program main
common/structure/i, x
integer i
real x
end

g77 -c file.f
nm file.o

00000000 T MAIN__
U s_stop
00000008 C structure_

The common block named structure is identified by the symbol
structure_. In your C program, define a global variable

C doesn't have global variables. Get your terms straight.

struct {
int i;
float x;
} structure_;

so that you can reference the data members of the common block

structure_.i

and

structure_.x

Fortran is NOT on topic in c.l.c. Are you doing this just to
avoid having people around who know that language criticize your
statements?

*** WARN WARN WARN ***
Anything Trollsdale posts is usually wrong.

 

[glen herrmannsfeldt]

Christopher M. Lusardi wrote:

I know about the convention of appending "_" to c routine names, but
how do I access Fortran global variables in c?

The actual methods tend to be system dependent, but the
most obvious one is that a COMMON corresponds to an
extern struct.

One complication is that C allows padding and Fortran
does not.

-- glen