sdaiGetAggrByIndex

valueType argument to specify what type of data caller wants to get and value argument where the caller should provide a buffer, and the function will write the result to. Table 1 shows type of buffer the caller should provide depending on the valueType for sdaiGetAggrByIndex, and it works similarly for all get-functions. Note: with SDAI API it is impossible to check buffer type at compilation or execution time and this is responsibility of a caller to ensure that requested valueType is matching with the value argument, a mismatch will lead to unpredictable results. The Table 2 shows what valueType can be fulfilled depending on actual model data. On success get-function will return non-zero. More precisely, according to ISO 10303-24-2001 on success they return content of value argument (*value) for sdaiADB, sdaiAGGR, or sdaiINSTANCE or value argument itself for other types (it has no useful meaning for C#). All get-functions return NULL and set value to 0 if model data are incompatible with requested valueType. Furthermore: - for unset ($) data all get-functions return NULL and set value to 0, except when valueType = sdaiEXPRESSSTRING - for derived (*), depending on engiEnableDerivedAttributes, and except valueType = sdaiEXPRESSSTRING: -- either calculate and follow these rues for calculated value -- or handles it as unset ($) - if valueType = sdaiEXPRESSSTRING and data is unset ($) or derived (*), get-function will return NULL but set value to "$" or "*" respectively for any engiEnableDerivedAttributes state

Table 1 – Required value buffer depending on valueType (on the example of sdaiGetAggrByIndex but valid for all get-functions)

valueType               C/C++                                                               C#

sdaiINTEGER             int_t val;                                                          int_t val;
                        sdaiGetAggrByIndex (aggregate, index, sdaiINTEGER, &val);           ifcengine.sdaiGetAggrByIndex (aggregate, index, ifcengine.sdaiINTEGER, out val);

sdaiREAL or sdaiNUMBER  double val;                                                         double val;
                        sdaiGetAggrByIndex (aggregate, index, sdaiREAL, &val);              ifcengine.sdaiGetAggrByIndex (aggregate, index, ifcengine.sdaiREAL, out val);

sdaiBOOLEAN             SdaiBoolean val;                                                    bool val;
                        sdaiGetAggrByIndex (aggregate, index, sdaiBOOLEAN, &val);           ifcengine.sdaiGetAggrByIndex (aggregate, index, ifcengine.sdaiBOOLEAN, out val);

sdaiLOGICAL             const TCHAR* val;                                                   string val;
                        sdaiGetAggrByIndex (aggregate, index, sdaiLOGICAL, &val);           ifcengine.sdaiGetAggrByIndex (aggregate, index, ifcengine.sdaiLOGICAL, out val);

sdaiENUM                const TCHAR* val;                                                   string val;
                        sdaiGetAggrByIndex (aggregate, index, sdaiENUM, &val);              ifcengine.sdaiGetAggrByIndex (aggregate, index, ifcengine.sdaiENUM, out val);

sdaiBINARY              const TCHAR* val;                                                   string val;
                        sdaiGetAggrByIndex (aggregate, index, sdaiBINARY, &val);            ifcengine.sdaiGetAggrByIndex (aggregate, index, ifcengine.sdaiBINARY, out val);

sdaiSTRING              const char* val;                                                    string val;
                        sdaiGetAggrByIndex (aggregate, index, sdaiSTRING, &val);            ifcengine.sdaiGetAggrByIndex (aggregate, index, ifcengine.sdaiSTRING, out val);

sdaiUNICODE             const wchar_t* val;                                                 string val;
                        sdaiGetAggrByIndex (aggregate, index, sdaiUNICODE, &val);           ifcengine.sdaiGetAggrByIndex (aggregate, index, ifcengine.sdaiUNICODE, out val);

sdaiEXPRESSSTRING       const char* val;                                                    string val;
                        sdaiGetAggrByIndex (aggregate, index, sdaiEXPRESSSTRING, &val);     ifcengine.sdaiGetAggrByIndex (aggregate, index, ifcengine.sdaiEXPRESSSTRING, out val);

sdaiINSTANCE            SdaiInstance val;                                                   int_t val;
                        sdaiGetAggrByIndex (aggregate, index, sdaiINSTANCE, &val);          ifcengine.sdaiGetAggrByIndex (aggregate, index, ifcengine.sdaiINSTANCE, out val);

sdaiAGGR                SdaiAggr aggr;                                                      int_t aggr;
                        sdaiGetAggrByIndex (aggregate, index, sdaiAGGR, &aggr);             ifcengine.sdaiGetAggrByIndex (aggregate, index, ifcengine.sdaiAGGR, out aggr);

sdaiADB                 SdaiADB adb = sdaiCreateEmptyADB();                                 int_t adb = 0;  //  it is important to initialize
                        sdaiGetAggrByIndex (aggregate, index, sdaiADB, adb);                ifcengine.sdaiGetAggrByIndex (aggregate, index, ifcengine.sdaiADB, out adb);        
                        sdaiDeleteADB (adb);

                        SdaiADB adb = nullptr;  //  it is important to initialize
                        sdaiGetAggrByIndex (aggregate, index, sdaiADB, &adb);

Table 2 - valueType can be requested depending on actual model data.

valueType       Works for following values in the model
                  integer      real     .T. or .F.     .U.      other enum    binary      string     instance      list
sdaiINTEGER         Yes         Yes *        .           .           .           .           .           .           .
sdaiREAL            Yes         Yes          .           .           .           .           .           .           .
sdaiNUMBER          Yes         Yes          .           .           .           .           .           .           .
sdaiBOOLEAN          .           .          Yes          .           .           .           .           .           .
sdaiLOGICAL          .           .          Yes         Yes          .           .           .           .           .
sdaiENUM             .           .          Yes         Yes         Yes          .           .           .           .
sdaiBINARY           .           .           .           .           .          Yes          .           .           .
sdaiSTRING          Yes         Yes         Yes         Yes         Yes         Yes         Yes          .           .
sdaiUNICODE         Yes         Yes         Yes         Yes         Yes         Yes         Yes          .           .
sdaiEXPRESSSTRING   Yes         Yes         Yes         Yes         Yes         Yes         Yes          .           .
sdaiINSTANCE         .           .           .           .           .           .           .          Yes          .
sdaiAGGR             .           .           .           .           .           .           .           .          Yes
sdaiADB             Yes         Yes         Yes         Yes         Yes         Yes         Yes         Yes         Yes