ToC path:

Database Calculator Callback Handlers

The Database Calculator functions mco_calc_cinfo_browse() and mco_calc_iinfo_browse() require callback functions to process the information relative to a specific class or index. They have the following prototypes:

 
    typedef void (*mco_calc_cinfo_h)(mco_calc_t * calc, mco_cc_t * cls, 
                       mco_cc_info_t * info, void * ctx);
                         
    typedef void (*mco_calc_iinfo_h)(mco_calc_t * calc, mco_index_stat_t * istat, 
                       void * ctx);

Note that the index istat parameter is of type mco_index_stat_t defined in file mco.h and the context parameter ctx is to allow possible additional application-specific data to be passed into the handler function.

An example of these handler functions are the following:

     
    static void class_print(mco_calc_t *calc, mco_cc_t *cls,
                    mco_cc_info_t *info, void *unused)
    {
        printf(" -> %s%s:\n", (info->is_pers ? "[PERSISTENT] " : ""), cls->cc_name);
        ...
    }
     
    static void index_print(mco_calc_t *calc, mco_cc_t *cls,
                    mco_index_stat_t *istat, void *unused)
    {
        int tmp, psize = 0;
        char *str = NULL, c;
 
        if ((istat->type & MCO_IDXST_TYPE_MASK) == MCO_IDXST_TYPE_MEM) {
            str = "Inmem";
            psize = calc->pg_size;
        }
        else if ((istat->type & MCO_IDXST_TYPE_MASK) == MCO_IDXST_TYPE_DISK) {
            str = "Disk";
            psize = _disk_page_size;
        }
 
        printf(" -> %s [%s ", istat->plabel, str);
        ...
    }