Mega Code Archive
Synchronously launching an application
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Title: Synchronously launching an application
Question: How to run a program and wait for it to terminate ?
Answer:
Here two methods of running another application and waiting for it to terminate (as opposed to ShellExecute, which only starts the specified program, and returns immediately).
{the code speaks for itself, but try to look up API functions you don't recognize}
{the first example, based on WaitForSingleObject}
function WinExecAndWait32_v1(FileName: string; Visibility: integer):
Cardinal; {integer}
var
zAppName: array[0..512] of char;
zCurDir: array[0..255] of char;
WorkDir: string;
StartupInfo: TStartupInfo;
ProcessInfo: TProcessInformation;
begin
StrPCopy(zAppName, FileName);
GetDir(0, WorkDir);
StrPCopy(zCurDir, WorkDir);
FillChar(StartupInfo, Sizeof(StartupInfo), #0);
StartupInfo.cb := Sizeof(StartupInfo);
StartupInfo.dwFlags := STARTF_USESHOWWINDOW;
StartupInfo.wShowWindow := Visibility;
if not CreateProcess(nil,
zAppName, { pointer to command line string }
nil, { pointer to process security attributes }
nil, { pointer to thread security attributes }
true, { handle inheritance flag }
CREATE_NEW_CONSOLE or { creation flags }
NORMAL_PRIORITY_CLASS,
nil, { pointer to new environment block }
nil, { pointer to current directory name, PChar}
StartupInfo, { pointer to STARTUPINFO }
ProcessInfo) { pointer to PROCESS_INF }
then Result := INFINITE {-1} else
begin
WaitforSingleObject(ProcessInfo.hProcess, INFINITE);
GetExitCodeProcess(ProcessInfo.hProcess, Result);
CloseHandle(ProcessInfo.hProcess); { to prevent memory leaks }
CloseHandle(ProcessInfo.hThread);
end;
end;
{the second example, based on PeekMessage(msg,,,,PM_REMOVE)-DispatchMessage(msg)}
function WinExecAndWait32_v2(FileName: string; Visibility: integer):
Cardinal; {integer}
var
zAppName: array[0..512] of char;
zCurDir: array[0..255] of char;
WorkDir: string;
StartupInfo: TStartupInfo;
ProcessInfo: TProcessInformation;
Msg: TagMsg;
ExitCode: cardinal;
begin
StrPCopy(zAppName, FileName);
GetDir(0, WorkDir);
StrPCopy(zCurDir, WorkDir);
FillChar(StartupInfo, Sizeof(StartupInfo), #0);
StartupInfo.cb := Sizeof(StartupInfo);
StartupInfo.dwFlags := STARTF_USESHOWWINDOW; // STARTF_FORCEONFEEDBACK;
StartupInfo.wShowWindow := Visibility;
if CreateProcess(nil, { and once more: }
zAppName, { pointer to command line string }
nil, { pointer to process security attributes }
nil, { pointer to thread security attributes }
false, { handle inheritance flag }
NORMAL_PRIORITY_CLASS, { creation flags }
nil, { pointer to the new environment block }
nil, { current directory name }
StartupInfo, { pointer to STARTUPINFO }
ProcessInfo) then { pointer to PROCESS_INF }
begin
repeat
while PeekMessage(Msg, 0, 0, 0, PM_REMOVE) do
begin
if (Msg.message = WM_QUIT) then
Result := Msg.wParam;
TranslateMessage(msg);
Dispatchmessage(msg);
Sleep(100); {your choice}
end;
GetExitCodeProcess(ProcessInfo.hProcess, ExitCode);
until (ExitCode STILL_ACTIVE);
CloseHandle(ProcessInfo.hThread);
CloseHandle(ProcessInfo.hProcess);
Result := 0;
end
else begin
Result := GetLastError;
end;
end;
Bogdan Grigorescu - BogdanG@gmail.com
BG Remote Programming Group
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