Hi,

I have a c dll which I need to link to from my C# code.  I just want
to warn you guys I am not very well versed in C or C++ so any help
would be greatly appreciated.

I wanted to know if the structure I have shown should be modeled as a
Struct or as a Class in C#.  Also, since there are callbacks from the
C side, how do I have to maintain my c# objects lifetime ?  Finally,
it is the question, of how this struct should look in C#.  Again, any
help would be greatly appreciated.  Thanks in advance.

#define INTERNAL_USE_ONLY  /* For marking fields designated as
internal use only */

typedef struct _ARM_ROUND {
   double armr_unit   ;  /* unit of the rounding operation. eg: 0.125
*/
   char   armr_target ;
#define TARGET_INDEX      1
#define TARGET_NETRATE    2
#define TARGET_GROSSRATE  3
   char   armr_method ;
#define METHOD_CEIL       1
#define METHOD_FLOOR      2
#define METHOD_ROUND      3
   char  *armr_next   ;  /* to next in link list */
   }  ARM_ROUND ;

typedef struct _ARMI_INFO {
   char *armi_next ;              /* Ptr to next armp in linked list
*/
   int armi_stage_start_mo ;
   int armi_index ;
   char armi_index_subname[MAX_INDEXSUBNAME_CHARS+1]; /* LOOKBKnn or
explicit subname  */
   char armi_amort_type ;
   int armi_ntillreset ;
   int armi_resetper ;
   int armi_paym_ntillreset ;
   double armi_init_percap ;
   int    armi_init_resetper ;
   char armi_negam_limit_action  ;
   double *misc_uservals ;
   int *tranche_freqs
   double **vindexs
   char **class_vsubclasses ;    /* the nodes directly under this
class*/
   char      pibond_issue_description     [52]  ;
   int optrt_nums[OPTR_MAX_TARGETS+1]
   INDEX **vindex_info ;   /* vector of index info structures */
   ARM_ROUND *armi_roundp;
   char *grp_fullname ;           /* descriptive name of the group */
   int ((CALLBACK_PREFIX *script_sym_fcn)(char *, char *, int,
int));  /* optional user callback fcn */

   /* internal fields */
INTERNAL_USE_ONLY    double armi_subpool_frac ;
INTERNAL_USE_ONLY    double armi_subpool_netrate ;
INTERNAL_USE_ONLY    double armi_subpool_servrate ;
   }  ARM_INFO ;