Fortran Interface

Using the opatIO-cpp module we provide a rudimentary fotran interface. Note that this interface does not support all the same feature as the C++ interface and will not recive the same degree of support and development that the C++ and python interfaces will. The Fortran interface is primarily intended for use in legacy code bases.

Example: Reading an OPAT File in Fortran

Below is an example program demonstrating how to use the Fortran interface to load an OPAT file, retrieve a table, and access its data.

Key Steps:

1. Load the OPAT file using load_opat_file.
2. Retrieve a specific table using get_opat_table, providing an index vector and a tag.
3. Check the returned table structure for errors.
4. Access the table's data via associated pointers (row_values, col_values, data).
5. Clean up resources using free_opat_file.

Example Code:

program opat_read_example
    use opat_interface_module
    use, intrinsic :: iso_c_binding
    implicit none
 
    CHARACTER(LEN=256) :: filename
    REAL(C_DOUBLE), TARGET :: index_vec(2)
    CHARACTER(LEN=4) :: tag
    TYPE(opat_table_f_type) :: my_table
    INTEGER :: load_status
 
    filename = 'gs98hz.opat'
    index_vec = [0.9, 0.08]
    tag = "data"
 
    load_status = load_opat_file(trim(filename))
    IF (load_status /= 0) THEN
        print *, "ERROR: Failed to load OPAT file."
        stop 1
    END IF
 
    CALL get_opat_table(index_vec, tag, my_table)
    IF (my_table%error_code /= 0) THEN
        print *, "ERROR retrieving table."
    ELSE
        print *, "Table retrieved successfully!"
        ! Access table data here...
    END IF
 
    CALL free_opat_file()
end program

Notes:

• Always check the error_code in the returned table structure to ensure the operation was successful.
• Ensure pointers (row_values, col_values, data) are associated before accessing them.
• Call free_opat_file to release resources when done.