RegisterApplicationRestart function

Registers the active instance of an application for restart.


HRESULT RegisterApplicationRestart(
  PCWSTR pwzCommandline,
  DWORD  dwFlags



A pointer to a Unicode string that specifies the command-line arguments for the application when it is restarted. The maximum size of the command line that you can specify is RESTART_MAX_CMD_LINE characters. Do not include the name of the executable in the command line; this function adds it for you.

If this parameter is NULL or an empty string, the previously registered command line is removed. If the argument contains spaces, use quotes around the argument.


This parameter can be 0 or one or more of the following values.

Value Meaning
Do not restart the process if it terminates due to an unhandled exception.
Do not restart the process if it terminates due to the application not responding.
Do not restart the process if it terminates due to the installation of an update.
Do not restart the process if the computer is restarted as the result of an update.

Return Value

This function returns S_OK on success or one of the following error codes.

Return code Description
Internal error.
The specified command line is too long.


Your initial registration for restart must occur before the application encounters an unhandled exception or becomes unresponsive. You could then call this function from inside your recovery callback to update the command line.

For a Windows application that is being updated, the last opportunity to call this function is while processing the WM_QUERYENDSESSION message. For a console application that is being updated, the registration must occur before the installer tries to shutdown the application (you need to keep the registration current; you cannot call this function when handling the CTRL_C_EVENT notification).

If you register for restart and the application encounters an unhandled exception or is not responsive, the user is offered the opportunity to restart the application; the application is not automatically restarted without the user's consent. However, if the application is being updated and requires a restart, the application is restarted automatically.

To prevent cyclical restarts, the system will only restart the application if it has been running for a minimum of 60 seconds.

Note that for an application to be restarted when the update requires a computer restart, the installer must call the ExitWindowsEx function with the EWX_RESTARTAPPS flag set or the InitiateShutdown function with the SHUTDOWN_RESTARTAPPS flag set.


Minimum supported client Windows Vista [desktop apps only]
Minimum supported server Windows Server 2008 [desktop apps only]
Target Platform Windows
Header winbase.h (include Windows.h)
Library Kernel32.lib
DLL Kernel32.dll

See Also