get "undefined reference" with routines contained in a module

Hi,

I have two files, one is a module which *contains* (internal) functions and subroutines, the other is a main program:

file 1:

MODULE mod
[declaration part]
CONTAINS
SUBROUTINE func1()
[code]
END SUBROUTINE func1
END MODULE mod

file 2:

PROGRAM test
USE mod
CALL func1()
END PROGRAM test

If I compile/link both files at the same time, as:

g95 mod.f90 test.f90

I get the expected result, but if I compile the files separately, first

g95 -c mod.f90

and then the main program with

g95 test.f90

I get a "undefined reference" error. My goal is to use modules like libraries in F77 times: Compile modules with internal routines, put the *.mod files into the lib directory (e.g.) and use them with the "-I" option as a library for other main programs. Unfortunately only the declaration part is visible in the separate compiled main program. The contained routine part is not.

Do I have to use interface blocks to reach my goal although I used internal functions/subroutines? BTW: The subroutines don't contain user-defined data types, etc which would need interface blocks.

Do I have to write a single module with the public declaration part and all interface blocks of all (external) functions/subroutines. Write external subroutines/functions with the USE statement of the single module mentioned above. Make a library of these subroutines/functions. Use the USE statement in the main program.

Or maybe I haven't understood the new module architecture of Fortran 90 correctly.


Best regards,

Hani
.

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