Prototype and description of the function setcalcextra()

(This function needs no unlocking)

setcalcextra()
Switching the calculation of Extra Parameters during coordinate
transformations.

Prototype of the DLL function in C++ syntax (attend lower case!):
extern "C" __declspec(dllimport) unsigned long __stdcall setcalcextra(
     unsigned long lSwitch);

Prototype of the DLL function in Visual Objects syntax:
_DLL function setcalcextra(;
     lSwitch as logic);                    // 4 Byte
as logic pascal:geodll32.setcalcextra      // 4 Byte


Additional (extra) parameters can be calculated during the execution of
coordinate transformations. Because the permanent calculation of the
Extra Parameters would slightly reduce the execution speed of GeoDLL, these
calculations can be switched on and off. The Extra Parameters can be called
by the function coordcalcextra(). For more information, see the description
of the function coordcalcextra().

The following Extra Parameters are available:
   Longitude of the Geographical Point coordinate in the source system.
   Latitude of the Geographical Point coordinate in the source system.
   Longitude of Origin Center in the source System.
   Meridian Convergence at the Geographical Point in the source system.
   Longitude of the Geographical Point coordinate in the target system.
   Latitude of the Geographical Point coordinate in the target system.
   Longitude of Origin Center in the target System.
   Meridian Convergence at the Geographical Point in the target system.

If the value TRUE is passed in lSwitch, the calculation of the Extra
Parameters is performed during all coordinate transformations. In addition,
Extra Parameters that are still present are reset to zero.

If the value FALSE is passed in lSwitch, the calculation of the Extra
Parameters during coordinate transformations is blocked. The last
calculated Extra Parameters are retained and are available for retrieval
with the function coordcalcextra().


The parameters are passed and/or returned as follows:
lSwitch       Switch for the calculation of additional parameters.
TRUE          Calculation on.
FALSE         Calculation off.
              (default)

returnVal   In case of an error the function returns FALSE, otherwise TRUE.


Unlocking:
This function needs no unlocking.