wxWidgets/interface/snglinst.h
2008-03-20 13:45:17 +00:00

108 lines
3.4 KiB
Objective-C

/////////////////////////////////////////////////////////////////////////////
// Name: snglinst.h
// Purpose: interface of wxSingleInstanceChecker
// Author: wxWidgets team
// RCS-ID: $Id$
// Licence: wxWindows license
/////////////////////////////////////////////////////////////////////////////
/**
@class wxSingleInstanceChecker
@wxheader{snglinst.h}
wxSingleInstanceChecker class allows to check that only a single instance of a
program is running. To do it, you should create an object of this class. As
long as this object is alive, calls to
wxSingleInstanceChecker::IsAnotherRunning from
other processes will return @true.
As the object should have the life span as big as possible, it makes sense to
create it either as a global or in wxApp::OnInit. For
example:
@code
bool MyApp::OnInit()
{
const wxString name = wxString::Format("MyApp-%s", wxGetUserId().c_str());
m_checker = new wxSingleInstanceChecker(name);
if ( m_checker-IsAnotherRunning() )
{
wxLogError(_("Another program instance is already running, aborting."));
delete m_checker; // OnExit() won't be called if we return @false
m_checker = @NULL;
return @false;
}
... more initializations ...
return @true;
}
int MyApp::OnExit()
{
delete m_checker;
return 0;
}
@endcode
Note using wxGetUserId() to construct the name: this
allows different user to run the application concurrently which is usually the
intended goal. If you don't use the user name in the wxSingleInstanceChecker
name, only one user would be able to run the application at a time.
This class is implemented for Win32 and Unix platforms (supporting @c fcntl()
system call, but almost all of modern Unix systems do) only.
@library{wxbase}
@category{misc}
*/
class wxSingleInstanceChecker
{
public:
/**
Like Create() but without
error checking.
*/
wxSingleInstanceChecker(const wxString& name,
const wxString& path = wxEmptyString);
/**
Destructor frees the associated resources.
Note that it is not virtual, this class is not meant to be used polymorphically
*/
~wxSingleInstanceChecker();
/**
Initialize the object if it had been created using the default constructor.
Note that you can't call Create() more than once, so calling it if the
@ref wxsingleinstancechecker() "non default ctor"
had been used is an error.
@param name
must be given and be as unique as possible. It is used as the
mutex name under Win32 and the lock file name under Unix.
GetAppName() and wxGetUserId()
are commonly used to construct this parameter.
@param path
is optional and is ignored under Win32 and used as the directory to
create the lock file in under Unix (default is
wxGetHomeDir())
@returns Returns @false if initialization failed, it doesn't mean that
another instance is running - use IsAnotherRunning()
to check for it.
*/
bool Create(const wxString& name,
const wxString& path = wxEmptyString);
/**
Returns @true if another copy of this program is already running, @false
otherwise.
*/
bool IsAnotherRunning() const;
};