3c5487b144
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@27542 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
131 lines
4.5 KiB
TeX
131 lines
4.5 KiB
TeX
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%% Name: snglinst.tex
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%% Purpose: wxSingleInstanceChecker documentation
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%% Author: Vadim Zeitlin
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%% Modified by:
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%% Created: 08.06.01
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%% RCS-ID: $Id$
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%% Copyright: (c) 2001 Vadim Zeitlin
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%% License: wxWidgets license
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\section{\class{wxSingleInstanceChecker}}\label{wxsingleinstancechecker}
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wxSingleInstanceChecker class allows to check that only a single instance of a
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program is running. To do it, you should create an object of this class. As
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long as this object is alive, calls to
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\helpref{IsAnotherRunning()}{wxsingleinstancecheckerisanotherrunning} from
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other processes will return {\tt true}.
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As the object should have the life span as big as possible, it makes sense to
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create it either as a global or in \helpref{wxApp::OnInit}{wxapponinit}. For
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example:
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\begin{verbatim}
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bool MyApp::OnInit()
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{
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const wxString name = wxString::Format("MyApp-%s", wxGetUserId().c_str());
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m_checker = new wxSingleInstanceChecker(name);
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if ( m_checker->IsAnotherRunning() )
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{
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wxLogError(_("Another program instance is already running, aborting."));
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return false;
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}
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... more initializations ...
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return true;
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}
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int MyApp::OnExit()
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{
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delete m_checker;
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return 0;
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}
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\end{verbatim}
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Note using \helpref{wxGetUserId()}{wxgetuserid} to construct the name: this
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allows different user to run the application concurrently which is usually the
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intended goal. If you don't use the user name in the wxSingleInstanceChecker
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name, only one user would be able to run the application at a time.
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This class is implemented for Win32 and Unix platforms (supporting {\tt fcntl()}
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system call, but almost all of modern Unix systems do) only.
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\wxheading{Derived from}
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No base class
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\wxheading{Include files}
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<wx/snglinst.h>
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\latexignore{\rtfignore{\wxheading{Members}}}
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\membersection{wxSingleInstanceChecker::wxSingleInstanceChecker}\label{wxsingleinstancecheckerctor}
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\func{}{wxSingleInstanceChecker}{\void}
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Default ctor, use \helpref{Create()}{wxsingleinstancecheckercreate} after it.
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\membersection{wxSingleInstanceChecker::wxSingleInstanceChecker}\label{wxsingleinstancecheckerwxsingleinstancechecker}
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\func{}{wxSingleInstanceChecker}{\param{const wxString\& }{name}, \param{const wxString\& }{path = wxEmptyString}}
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Like \helpref{Create()}{wxsingleinstancecheckercreate} but without
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error checking.
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\membersection{wxSingleInstanceChecker::Create}\label{wxsingleinstancecheckercreate}
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\func{bool}{Create}{\param{const wxString\& }{name}, \param{const wxString\& }{path = wxEmptyString}}
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Initialize the object if it had been created using the default constructor.
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Note that you can't call Create() more than once, so calling it if the
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\helpref{non default ctor}{wxsingleinstancecheckerwxsingleinstancechecker}
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had been used is an error.
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\wxheading{Parameters}
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\docparam{name}{must be given and be as unique as possible. It is used as the
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mutex name under Win32 and the lock file name under Unix.
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\helpref{GetAppName()}{wxappgetappname} and \helpref{wxGetUserId()}{wxgetuserid}
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are commonly used to construct this parameter.}
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\docparam{path}{is optional and is ignored under Win32 and used as the directory to
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create the lock file in under Unix (default is
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\helpref{wxGetHomeDir()}{wxgethomedir})}
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\wxheading{Return value}
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Returns {\tt false} if initialization failed, it doesn't mean that another
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instance is running - use
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\helpref{IsAnotherRunning()}{wxsingleinstancecheckerisanotherrunning} to check
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for it.
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\wxheading{Note}
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One of possible reasons while Create may fail on Unix is that the lock file
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used for checking already exists but was not created by the user.
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Therefore applications shouldn't treat failure of this function as fatal
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condition, because doing so would open them to the possibility of a Denial of
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Service attack. Instead, they should alert the user about the problem and
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offer to continue execution without checking if another instance is running.
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\membersection{wxSingleInstanceChecker::IsAnotherRunning}\label{wxsingleinstancecheckerisanotherrunning}
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\constfunc{bool}{IsAnotherRunning}{\void}
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Returns {\tt true} if another copy of this program is already running, {\tt
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false} otherwise.
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\membersection{wxSingleInstanceChecker::\destruct{wxSingleInstanceChecker}}\label{wxsingleinstancecheckerdtor}
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\func{}{\destruct{wxSingleInstanceChecker}}{\void}
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Destructor frees the associated resources.
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Note that it is not virtual, this class is not meant to be used polymorphically
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