initialiser Class Template Reference
[COM Utility Library]

#include <comstl/util/initialisers.hpp>

Detailed Description

template<typename IP, typename XP>
class comstl::initialiser< IP, XP >

Initialises the COM libraries.

This class is used to initialise the COM libraries. It can respond to CoInitializeEx argument flags when translated in a DCOM build.

It is specialised for COM or OLE library initialisation, and with or without throwing an exception on failure, in the following typedefs:

com_init - initialises the COM libraries; throws an instance of com_initialisation_exception on failure
com_init_nothrow - initialises the COM libraries; does not throw on failure
ole_init - initialises the OLE libraries; throws an instance of com_initialisation_exception on failure
ole_init_nothrow - initialises the OLE libraries; does not throw on failure

It is commonly used within main() (for a CLI program), or WinMain() (for a GUI program). A typical program structure is shown as follows:

#include <comstl/util/initialisers.hpp>

#include <stdlib.h>

static int main_(int argc, char **argv)
{
  . . . // main application functionality
}

int main(int argc, char **argv)
{
  try
  {
    comstl::com_init  init; // Initialise the COM libraries

    return main_(argc, argv);
  }
  catch(comstl::com_initialisation_exception &x) // COM library initialisation failed
  {
    return EXIT_FAILURE;
  }
  catch(std::exception &x) // other failures from main_()
  {
    return EXIT_FAILURE;
  }
}

In practice, initialisation failure of the COM libraries is unheard of, so you can probably dispense with the specific catch clause shown above, and rely on comstl::com_initialisation_exception being caught by the std::exception clause.

See also:: comstl::

Examples:: by_library/com_utility/creation_functions/creation_functions.cpp, by_library/com_utility/rot_functions/rot_functions.cpp, by_library/memory/com_memory_functions/com_memory_functions.cpp, and by_project/comstl/comstl.cpp.


Member Types
typedef IP	initialisation_policy_type
	The initialiation policy type.
typedef XP	exception_policy_type
	The exception type.
typedef exception_policy_type::thrown_type	thrown_type
	The thrown type.
Public Member Functions
Construction
	initialiser ()
	Initialises via CoInitialize().
	~initialiser () throw ()
	Uninitialises via CoUninitialize().
Attributes
bool	is_initialised () const
	Reflects whether the COM libraries were initialised.
bool	operator! () const
	Reflects whether the COM libraries were not initialised.
HRESULT	get_HRESULT () const
	The result of the call to CoInitialize()/CoInitializeEx().