Initializing and Deinitializing the API

Initialization

The first thing you must do when using the SCA is to start the 3rd party libraries startup functions:

dca::InitCUrl();
dca::SetOpenSslCallbacks();

(see also Initialization of 3rd party libraries)

Next step is to set up a dca::DcaInstance object. This class encapsulates the API as a whole.

To create the instance fill out a dca::InitData structure, and call the function dca::DcaInstance::create().

Note that the provided directories are (once initialized) not changeable for this instance.

The use of two or more DcaInstance objects in the same process (using the same initialization directory) is currently not supported.

Deinitialization

The SCA will be deinitialized automatically once the DcaInstance object goes out of scope. For more information on DCA startup and shutdown, Please refer to Startup/Shutdown sequence.

Before going out of scope, call the Deinitilization functions of the 3rd party libraries in reverse order:

dca::UnsetOpenSslCallbacks();
dca::DeinitCUrl();

Sample code

The following code demonstrates how to initialize the SCA.

#include <dca_base.h>
#include <dca_callbacks.h>
 
// assume the DCA has been installed to the ~/dca directory
#define DCA_INSTALLDIR  "~/dca"
#define DCA_BINDIR      DCA_INSTALLDIR"/bin/linux"
#define DCA_INITDIR     DCA_INSTALLDIR"/init"
#define DCA_LOGDIR      "./logs"
 
void main()
{
        try {
                // required 3rd party library startups
                dca::InitCUrl();
                dca::SetOpenSslCallbacks();
                // set up the required directories
                dca::InitData myInitData;
                myInitData.binDir       = DCA_BINDIR;
                myInitData.initDir      = DCA_INITDIR;
                myInitData.logDir       = DCA_LOGDIR;
 
                // start up DCA API
                dca::DcaInstance myDca = dca::DcaInstance::create( myInitData );
                ...
                // when going out of scope, myDca will be automatically deinitialized
        }
        catch( const dca::ExDca& ex ) {
                cout << "DCA error occurred (Error code: " << ex.getReturnCode() <<
                        ", Description: " << ex.getDescription() << ")." << endl;
        }
        // required 3rd party library shutdowns
        dca::UnsetOpenSslCallbacks();
        dca::DeinitCUrl();
}