How to ensure only a single instance of my application runs? - delphi

Is there support in the Delphi XE VCL for ensuring only a single instance of an application is running?
In the past, I've used library code to control a Mutex which has always seemed complicated. As I'm starting a new project in Delphi XE, I wonder if I need to dig up that old code, or if there is support built into XE already? Or is there another easy to apply code that is nice and modern?

You create a named Mutex when you start the application. Check GetLastError to see if an other instance is already running.
Put this code right after "begin" in your DPR file. Replace the GUID with one of your own. When I need a text constant that's unlikely to be used for anything else, I usually just hit Ctrl+G to get a GUID!
if CreateMutex(nil, True, '6EACD0BF-F3E0-44D9-91E7-47467B5A2B6A') = 0 then
RaiseLastOSError;
if GetLastError = ERROR_ALREADY_EXISTS then
Exit;
It might look like the code is leaking an handle because it's not saving the return of CreateMutex. It's not. Windows will automatically release the handle when our application is terminated, and that's absolutely fine with us.

I use JCL to do this:
program MyProgram;
uses
JclAppInst;
begin
JclAppInstances.CheckSingleInstance; // Added instance checking
Application.Initialize;
Application.CreateForm(TMainForm, MainForm);
Application.Run;
end.
Documentation for this, and the notification scheme, is at the JCL Wiki.

I use this, works in XE2 through to Alexandria, has the benefit of being able to bring the currently running instance to the front.
Those that say it shouldn't do that, well, given the last thing the user did was to try launch the app, bringing a currently running instance to the front makes sense
unit CheckPrevious;
interface
uses
Windows, SysUtils, WinSock;
function RestoreIfRunning(const AppHandle : THandle; MaxInstances : integer = 1) : boolean;
implementation
type
PInstanceInfo = ^TInstanceInfo;
TInstanceInfo = packed record
PreviousHandle : THandle;
RunCounter : integer;
end;
var
MappingHandle: THandle;
InstanceInfo: PInstanceInfo;
MappingName : string;
RemoveMe : boolean = True;
function RestoreIfRunning(const AppHandle : THandle; MaxInstances : integer = 1) : boolean;
begin
Result := True;
MappingName := StringReplace(ParamStr(0),'\','',[rfReplaceAll, rfIgnoreCase]);
MappingHandle := CreateFileMapping($FFFFFFFF,nil,PAGE_READWRITE,0,SizeOf(TInstanceInfo),PChar(MappingName));
if MappingHandle = 0 then
RaiseLastOSError
else
begin
if GetLastError <> ERROR_ALREADY_EXISTS then
begin
InstanceInfo := MapViewOfFile(MappingHandle,FILE_MAP_ALL_ACCESS,0,0,SizeOf(TInstanceInfo));
InstanceInfo^.PreviousHandle := AppHandle;
InstanceInfo^.RunCounter := 1;
Result := False;
end
else //already runing
begin
MappingHandle := OpenFileMapping(FILE_MAP_ALL_ACCESS, False, PChar(MappingName));
if MappingHandle <> 0 then
begin
InstanceInfo := MapViewOfFile(MappingHandle,FILE_MAP_ALL_ACCESS,0,0,SizeOf(TInstanceInfo));
if InstanceInfo^.RunCounter >= MaxInstances then
begin
RemoveMe := False;
if IsIconic(InstanceInfo^.PreviousHandle) then
ShowWindow(InstanceInfo^.PreviousHandle, SW_RESTORE);
SetForegroundWindow(InstanceInfo^.PreviousHandle);
end
else
begin
InstanceInfo^.PreviousHandle := AppHandle;
InstanceInfo^.RunCounter := 1 + InstanceInfo^.RunCounter;
Result := False;
end
end;
end;
end;
end;
initialization
finalization
//remove one instance
if RemoveMe then
begin
MappingHandle := OpenFileMapping(FILE_MAP_ALL_ACCESS, False, PChar(MappingName));
if MappingHandle <> 0 then
begin
InstanceInfo := MapViewOfFile(MappingHandle, FILE_MAP_ALL_ACCESS, 0, 0, SizeOf(TInstanceInfo));
InstanceInfo^.RunCounter := -1 + InstanceInfo^.RunCounter;
end
else
RaiseLastOSError;
end;
if Assigned(InstanceInfo) then
UnmapViewOfFile(InstanceInfo);
if MappingHandle <> 0 then
CloseHandle(MappingHandle);
end.
In your project DPR, add the CheckPrevious unit to the uses, then just after begin put the following
if RestoreIfRunning(Application.Handle, 1) then
Exit;
I have no idea of where this code originated, otherwise I would gladly credit the author. (A search of RestoreIfRunning may suggest it was from Zarko Gajic)

This is how i do it.
closeProc(extractfilename(paramstr(0)));
function TForm1.closeProc(pname : string): integer;
const
PROCESS_TERMINATE = $0001;
var
ContinueLoop: BOOL;
FSnapshotHandle: THandle;
FProcessEntry32: TProcessEntry32;
i : integer;
pname2 : string;
begin
try
Result := 0;
i := 0;
FSnapshotHandle := CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
FProcessEntry32.dwSize := SizeOf(FProcessEntry32);
ContinueLoop := Process32First(FSnapshotHandle, FProcessEntry32);
while Integer(ContinueLoop) <> 0 do
begin
pname2 := trim(UpperCase(ExtractFileName(FProcessEntry32.szExeFile)));
if ( pname2 = uppercase(pname)) then
if FProcessEntry32.th32ProcessID <> GetCurrentProcessId then
begin
Result := Integer(TerminateProcess(OpenProcess(PROCESS_TERMINATE, BOOL(0), FProcessEntry32.th32ProcessID), 0));
inc(i);
end;
ContinueLoop := Process32Next(FSnapshotHandle, FProcessEntry32);
if i > 50 then
break;
end;
CloseHandle(FSnapshotHandle);
except
end;
end;

Related

How to detect whether a SPECIFIC Delphi version is currently running?

In a 32-bit VCL application on Windows 10 in Delphi 11 Alexandria, I try to detect whether a specific Delphi version is currently running. So I used the Winapi.TlHelp32.CreateToolhelp32Snapshot function to search for "bds.exe":
function ProcessExists(exeFileName: string): Boolean;
var
ContinueLoop: Winapi.Windows.BOOL;
FSnapshotHandle: Winapi.Windows.THandle;
FProcessEntry32: Winapi.TlHelp32.TProcessEntry32;
begin
FSnapshotHandle := Winapi.TlHelp32.CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
FProcessEntry32.dwSize := System.SizeOf(FProcessEntry32);
ContinueLoop := Winapi.TlHelp32.Process32First(FSnapshotHandle, FProcessEntry32);
Result := False;
while Integer(ContinueLoop) <> 0 do
begin
if SameText(ExtractFileName(FProcessEntry32.szExeFile), ExeFileName) or SameText(FProcessEntry32.szExeFile, ExeFileName) then
begin
Result := True;
CodeSite.Send('ProcessExists: FProcessEntry32.szExeFile', FProcessEntry32.szExeFile);
BREAK;
end;
ContinueLoop := Process32Next(FSnapshotHandle, FProcessEntry32);
end;
Winapi.Windows.CloseHandle(FSnapshotHandle);
end;
...
CodeSite.Send('ProcessExists(ThisBdsExe)', ProcessExists('bds.exe'));
Unfortunately, FProcessEntry32.szExeFile returns only the FILENAME without the PATH information. So I get only the information whether Delphi is running, but NOT whether a specific Delphi version is running!
Is there any way to get the PATH information from the FProcessEntry32 structure?
Of course, I know the paths of each bds.exe that exists on my computer. But this does not work:
CodeSite.Send('ProcessExists(Delphi 11 bds.exe path)', ProcessExists('C:\Program Files (x86)\Embarcadero\Studio\22.0\bin\bds.exe'));
The API help for PROCESSENTRY32's szExeFile entry:
szExeFile
The name of the executable file for the process. To retrieve the full
path to the executable file, call the Module32First function and check
the szExePath member of the MODULEENTRY32 structure that is returned.
However, if the calling process is a 32-bit process, you must call the
QueryFullProcessImageName function to retrieve the full path of the
executable file for a 64-bit process.
So you need to make a Module32First call and currently at least BDS is a 32bit process so you don't need to use QueryFullProcessImageName even if your app is 32bit.
GetModuleFileNameEx worked for me:
function GetPathFromPID(const PID: cardinal): string;
var
hProcess: THandle;
path: array[0..MAX_PATH - 1] of char;
begin
hProcess := OpenProcess(PROCESS_QUERY_INFORMATION or PROCESS_VM_READ, false, PID);
if hProcess <> 0 then
try
if GetModuleFileNameEx(hProcess, 0, path, MAX_PATH) = 0 then
RaiseLastOSError;
result := path;
finally
CloseHandle(hProcess)
end
else
RaiseLastOSError;
end;
function ProcessExists(exeFileName: string): Boolean;
var
ContinueLoop: Winapi.Windows.BOOL;
FSnapshotHandle: Winapi.Windows.THandle;
FProcessEntry32: Winapi.TlHelp32.TProcessEntry32;
begin
FSnapshotHandle := Winapi.TlHelp32.CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
FProcessEntry32.dwSize := System.SizeOf(FProcessEntry32);
ContinueLoop := Winapi.TlHelp32.Process32First(FSnapshotHandle, FProcessEntry32);
Result := False;
var ThisExeName := ExtractFileName(exeFileName);
while Integer(ContinueLoop) <> 0 do
begin
if SameText(ExtractFileName(FProcessEntry32.szExeFile), ThisExeName) or SameText(FProcessEntry32.szExeFile, ThisExeName) then
begin
var ThisBdsExePath := GetPathFromPID(FProcessEntry32.th32ProcessID);
Result := SameText(exeFileName, ThisBdsExePath);
if Result then BREAK;
end;
ContinueLoop := Process32Next(FSnapshotHandle, FProcessEntry32);
end;
Winapi.Windows.CloseHandle(FSnapshotHandle);
end;

Delphi reboot Windows

I'm using Windows 10 and I am logged in as Administrator.
When I try to reboot the system, all it does is it logs me off.
ExitWindowsEx(EWX_REBOOT and EWX_FORCE, 0);
Can someone please tell me why is this not rebooting?
So it seems that even though I am a administrator I need to set the rights with the following function
function NTSetPrivilege(sPrivilege: string; bEnabled: Boolean): Boolean;
var
hToken: THandle;
TokenPriv: TOKEN_PRIVILEGES;
PrevTokenPriv: TOKEN_PRIVILEGES;
ReturnLength: Cardinal;
begin
Result := True;
// Only for Windows NT/2000/XP and later.
if not (Win32Platform = VER_PLATFORM_WIN32_NT) then Exit;
Result := False;
// obtain the processes token
if OpenProcessToken(GetCurrentProcess(),
TOKEN_ADJUST_PRIVILEGES or TOKEN_QUERY, hToken) then
begin
try
// Get the locally unique identifier (LUID) .
if LookupPrivilegeValue(nil, PChar(sPrivilege),
TokenPriv.Privileges[0].Luid) then
begin
TokenPriv.PrivilegeCount := 1; // one privilege to set
case bEnabled of
True: TokenPriv.Privileges[0].Attributes := SE_PRIVILEGE_ENABLED;
False: TokenPriv.Privileges[0].Attributes := 0;
end;
ReturnLength := 0; // replaces a var parameter
PrevTokenPriv := TokenPriv;
// enable or disable the privilege
AdjustTokenPrivileges(hToken, False, TokenPriv, SizeOf(PrevTokenPriv),
PrevTokenPriv, ReturnLength);
end;
finally
CloseHandle(hToken);
end;
end;
// test the return value of AdjustTokenPrivileges.
Result := GetLastError = ERROR_SUCCESS;
if not Result then
raise Exception.Create(SysErrorMessage(GetLastError));
end;
like this :
procedure TMain.Neustart1Click(Sender: TObject);
const
SE_SHUTDOWN_NAME = 'SeShutdownPrivilege';
begin
NTSetPrivilege(SE_SHUTDOWN_NAME, True);
ExitWindowsEx(EWX_REBOOT or EWX_FORCE, 0);
end;
Now it works.
I was looking for a better solution to the one I had done about 5 years ago (posted below), I needed to do some tweaking for it to run on latest Delphi, older Delphi versions simply use Windows.AdjustTokenPrivileges. Code below is tried and tested since windows XP. Be careful - it works, make sure you save your work before running!
//Uses WinApi.Windows on Latest Delphi 10.3.2
function MyExitWindows(RebootParam: Longword): Boolean;
var
TTokenHd: THandle;
TTokenPvg: TTokenPrivileges;
cbtpPrevious: DWORD;
rTTokenPvg: TTokenPrivileges;
pcbtpPreviousRequired: DWORD;
tpResult: Boolean;
const
SE_SHUTDOWN_NAME = 'SeShutdownPrivilege';
begin
if Win32Platform = VER_PLATFORM_WIN32_NT then
begin
tpResult := OpenProcessToken(GetCurrentProcess(),
TOKEN_ADJUST_PRIVILEGES or TOKEN_QUERY,
TTokenHd);
if tpResult then
begin
tpResult := LookupPrivilegeValue(nil,
SE_SHUTDOWN_NAME,
TTokenPvg.Privileges[0].Luid);
TTokenPvg.PrivilegeCount := 1;
TTokenPvg.Privileges[0].Attributes := SE_PRIVILEGE_ENABLED;
cbtpPrevious := SizeOf(rTTokenPvg);
pcbtpPreviousRequired := 0;
if tpResult then
//Older Delphi - replace the WinApi. to read WinApi.AdjustTokenPrivileges
WinApi.Windows.AdjustTokenPrivileges(TTokenHd,
False,
TTokenPvg,
cbtpPrevious,
rTTokenPvg,
pcbtpPreviousRequired);
end;
end;
Result := ExitWindowsEx(RebootParam, 0);
end;
//Examples
//Shutdown the computer
MyExitWindows(EWX_POWEROFF or EWX_FORCE);
//Reboot the computer
MyExitWindows(EWX_REBOOT or EWX_FORCE);

Suspend/resume processes as PsSuspend does

I hope this post is not a duplicate one. Let me explain:
I have considered the similar post How to pause / resume any external process under Windows? but with C++/Python preference and yet without an accepted answer as of the time of posting.
My Question:
I'm interested in a possible implementation in Delphi of the functionality provided by PsSuspend by Mark Russinovich of Windows Sysinternals.
Quotes:
PsSuspend lets you suspend processes on the local or a remote system,
which is desirable in cases where a process is consuming a resource
(e.g. network, CPU or disk) that you want to allow different processes
to use. Rather than kill the process that's consuming the resource,
suspending permits you to let it continue operation at some later
point in time.
Thank you.
Edit:
A partial implementation will do. Remote capability can be dropped.
You can try to use the following code. It uses the undocumented functions NtSuspendProcess and NtResumeProcess. I've tried it on Windows 7 64-bit from the 32-bit application built in Delphi 2009 and it works for me. Note that these functions are undocumented thus can be removed from future versions of Windows.
Update
The SuspendProcess and ResumeProcess wrappers from the following code are now functions and returns True if succeed, False otherwise.
type
NTSTATUS = LongInt;
TProcFunction = function(ProcHandle: THandle): NTSTATUS; stdcall;
const
STATUS_SUCCESS = $00000000;
PROCESS_SUSPEND_RESUME = $0800;
function SuspendProcess(const PID: DWORD): Boolean;
var
LibHandle: THandle;
ProcHandle: THandle;
NtSuspendProcess: TProcFunction;
begin
Result := False;
LibHandle := SafeLoadLibrary('ntdll.dll');
if LibHandle <> 0 then
try
#NtSuspendProcess := GetProcAddress(LibHandle, 'NtSuspendProcess');
if #NtSuspendProcess <> nil then
begin
ProcHandle := OpenProcess(PROCESS_SUSPEND_RESUME, False, PID);
if ProcHandle <> 0 then
try
Result := NtSuspendProcess(ProcHandle) = STATUS_SUCCESS;
finally
CloseHandle(ProcHandle);
end;
end;
finally
FreeLibrary(LibHandle);
end;
end;
function ResumeProcess(const PID: DWORD): Boolean;
var
LibHandle: THandle;
ProcHandle: THandle;
NtResumeProcess: TProcFunction;
begin
Result := False;
LibHandle := SafeLoadLibrary('ntdll.dll');
if LibHandle <> 0 then
try
#NtResumeProcess := GetProcAddress(LibHandle, 'NtResumeProcess');
if #NtResumeProcess <> nil then
begin
ProcHandle := OpenProcess(PROCESS_SUSPEND_RESUME, False, PID);
if ProcHandle <> 0 then
try
Result := NtResumeProcess(ProcHandle) = STATUS_SUCCESS;
finally
CloseHandle(ProcHandle);
end;
end;
finally
FreeLibrary(LibHandle);
end;
end;
There is no SuspendProcess API call in Windows. So what you need to do is:
Enumerate all the threads in the process. See RRUZ's answer for sample code.
Call SuspendThread for each of these threads.
In order to implement the resume part of the program, call ResumeThread for each thread.
There is a race condition for the "suspend all threads" implementation - what happens if the program you are trying to suspend creates one or more threads between the time that you create the snapshot and the time that you complete suspending?
You could loop, getting another snapshot and suspending any unsuspending threads, exiting only when you found none.
The undocumented function avoids this issue.
I just found the following snippets here (Author: steve10120).
I think they are valuables and I can't help posting them also as an alternative answer to my own question.
Resume Process:
function ResumeProcess(ProcessID: DWORD): Boolean;
var
Snapshot,cThr: DWORD;
ThrHandle: THandle;
Thread:TThreadEntry32;
begin
Result := False;
cThr := GetCurrentThreadId;
Snapshot := CreateToolhelp32Snapshot(TH32CS_SNAPTHREAD, 0);
if Snapshot <> INVALID_HANDLE_VALUE then
begin
Thread.dwSize := SizeOf(TThreadEntry32);
if Thread32First(Snapshot, Thread) then
repeat
if (Thread.th32ThreadID <> cThr) and (Thread.th32OwnerProcessID = ProcessID) then
begin
ThrHandle := OpenThread(THREAD_ALL_ACCESS, false, Thread.th32ThreadID);
if ThrHandle = 0 then Exit;
ResumeThread(ThrHandle);
CloseHandle(ThrHandle);
end;
until not Thread32Next(Snapshot, Thread);
Result := CloseHandle(Snapshot);
end;
end;
Suspend Process:
function SuspendProcess(PID:DWORD):Boolean;
var
hSnap: THandle;
THR32: THREADENTRY32;
hOpen: THandle;
begin
Result := FALSE;
hSnap := CreateToolhelp32Snapshot(TH32CS_SNAPTHREAD, 0);
if hSnap <> INVALID_HANDLE_VALUE then
begin
THR32.dwSize := SizeOf(THR32);
Thread32First(hSnap, THR32);
repeat
if THR32.th32OwnerProcessID = PID then
begin
hOpen := OpenThread($0002, FALSE, THR32.th32ThreadID);
if hOpen <> INVALID_HANDLE_VALUE then
begin
Result := TRUE;
SuspendThread(hOpen);
CloseHandle(hOpen);
end;
end;
until Thread32Next(hSnap, THR32) = FALSE;
CloseHandle(hSnap);
end;
end;
Disclaimer:
I didn't test them at all. Please enjoy and don't forget to feedback.

Not getting path of various system processes by GetModuleFileNameEx()

I have created this function to get the path of various network processes, like svchost, Firefox, etc. Here is the code:
function GetProcessPath(var pId:Integer):String;
var
Handle: THandle;
begin
Result := '';
try
Handle := OpenProcess(PROCESS_QUERY_INFORMATION or PROCESS_VM_READ, False, pID);
if Handle <> 0 then
begin
try
SetLength(Result, MAX_PATH);
if GetModuleFileNameEx(Handle, 0, PChar(Result), MAX_PATH) > 0 then
SetLength(Result, StrLen(PChar(Result)))
else
Result := '';
finally
CloseHandle(Handle);
end;
end;
except
on E:Exception do
ShowMessage(E.ClassName + ':' + E.Message);
end;
end;
My problem is that I do not get the path of all the processes. It works fine for getting the path of Firefox, and other similar user level processes. But for processes like alg, Svchost, I cannot get the path by this method. My guess is I must use some different API. How can I fix this problem?
I am using Windows XP, 32 bits.
You need to set debug privileges. Here is how it is done:
function NTSetPrivilege(sPrivilege: string; bEnabled: Boolean): Boolean;
var
hToken: THandle;
TokenPriv: TOKEN_PRIVILEGES;
PrevTokenPriv: TOKEN_PRIVILEGES;
ReturnLength: Cardinal;
begin
Result := True;
// Only for Windows NT/2000/XP and later.
if not (Win32Platform = VER_PLATFORM_WIN32_NT) then Exit;
Result := False;
// Obtain the processes token
if OpenProcessToken(GetCurrentProcess(),
TOKEN_ADJUST_PRIVILEGES or TOKEN_QUERY, hToken) then
begin
try
// Get the locally unique identifier (LUID) .
if LookupPrivilegeValue(nil, PChar(sPrivilege),
TokenPriv.Privileges[0].Luid) then
begin
TokenPriv.PrivilegeCount := 1; // One privilege to set
case bEnabled of
True: TokenPriv.Privileges[0].Attributes := SE_PRIVILEGE_ENABLED;
False: TokenPriv.Privileges[0].Attributes := 0;
end;
ReturnLength := 0; // Replaces a var parameter
PrevTokenPriv := TokenPriv;
// Enable or disable the privilege
AdjustTokenPrivileges(hToken, False, TokenPriv, SizeOf(PrevTokenPriv),
PrevTokenPriv, ReturnLength);
end;
finally
CloseHandle(hToken);
end;
end;
end;
NtSetPrivilege('SeDebugPrivilege', TRUE); // Call this on form create

Wait before ShellExecute is carried out?

I have a hopefully quick question: Is it possible to delay execution of ShellExecute a little bit?
I have an application with autoupdater. After it downloads all necessary files etc, it renames current files to *.OLD and the new as the previous. Simple enough. But then I need to delete those .OLD files. This 'cleanup' procedure is executed on MainForm.OnActivate (with a check if it is the first activate proc). But this apparently happens too fast (I get False from DeleteFile). This is the procedure:
procedure TUpdateForm.OKBtnClick(Sender: TObject);
const SHELL = 'ping 127.0.0.1 -n 2';
begin
ShellExecute(0,'open',pchar(SHELL+#13+Application.ExeName),nil,nil,SW_SHOWNORMAL);
Application.Terminate;
end;
This procedure is supposed to restart the application. I am certain that the deleting problem is caused by the quick start of the second application, because if I restart it myself, giving it a little time, the files get deleted normally.
tl;dr version: I need to call ShellExecute() which waits a bit (0.1 sec or so) and THEN executes the command.
Note
I tried using the -ping command to try to delay it, but it didn't work.
Thank you very much in advance
Edit: Rephrased
I need this to happen || First app closes; Wait 100 ms; second app opens ||. I need to call ShellExecute first, then wait until the calling application closes itself completely, then execute the shell (i.e. open second application)
You're doing an autopatcher right ?
I've had the same problem and this is how I bypassed it :
You run second app with argument "--delay" or something like that.
Second app handles argument "--delay" and sleeps for 100 ms, then continues running normally.
This routine is some utils code in our game engine. It can run an executable and optionally wait for it to exit. It will return its exit code:
function TSvUtils.FileExecute(ahWnd: Cardinal; const aFileName, aParams, aStartDir: string; aShowCmd: Integer; aWait: Boolean): Integer;
var
Info: TShellExecuteInfo;
ExitCode: DWORD;
begin
Result := -1;
FillChar(Info, SizeOf(Info), 0);
Info.cbSize := SizeOf(TShellExecuteInfo);
with Info do begin
fMask := SEE_MASK_NOCLOSEPROCESS;
Wnd := ahWnd;
lpFile := PChar(aFileName);
lpParameters := PChar(aParams);
lpDirectory := PChar(aStartDir);
nShow := aShowCmd;
end;
if ShellExecuteEx(#Info) then
begin
if aWait then
begin
repeat
Sleep(1);
Application.ProcessMessages;
GetExitCodeProcess(Info.hProcess, ExitCode);
until (ExitCode <> STILL_ACTIVE) or Application.Terminated;
CloseHandle(Info.hProcess);
Result := ExitCode;
end;
end
end;
Here is some code that can check to see if a process exists. So... current app calls the updater and terminates. The updater can check to see if old app has terminated and do it's thing (rename, update, delete, etc):
function TSvUtils.ProcessExists(const aExeFileName: string; aBringToForgound: Boolean=False): Boolean;
var
ContinueLoop: BOOL;
FSnapshotHandle: THandle;
FProcessEntry32: TProcessEntry32;
begin
FSnapshotHandle := CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
FProcessEntry32.dwSize := SizeOf(FProcessEntry32);
ContinueLoop := Process32First(FSnapshotHandle, FProcessEntry32);
Result := False;
while Integer(ContinueLoop) <> 0 do
begin
if ((UpperCase(ExtractFileName(FProcessEntry32.szExeFile)) =
UpperCase(aExeFileName)) or (UpperCase(FProcessEntry32.szExeFile) =
UpperCase(aExeFileName))) then
begin
if aBringToForgound then
EnumWindows(#BringToForgroundEnumProcess, FProcessEntry32.th32ProcessID);
Result := True;
end;
ContinueLoop := Process32Next(FSnapshotHandle, FProcessEntry32);
end;
CloseHandle(FSnapshotHandle);
end;
If you can use CreateProcess instead of ShellExecute, you can wait on the process handle. The process handle is signalled when the application exits. For example:
function ExecAndWait(APath: string; var VProcessResult: cardinal): boolean;
var
LWaitResult : integer;
LStartupInfo: TStartupInfo;
LProcessInfo: TProcessInformation;
begin
Result := False;
FillChar(LStartupInfo, SizeOf(TStartupInfo), 0);
with LStartupInfo do
begin
cb := SizeOf(TStartupInfo);
dwFlags := STARTF_USESHOWWINDOW or STARTF_FORCEONFEEDBACK;
wShowWindow := SW_SHOWDEFAULT;
end;
if CreateProcess(nil, PChar(APath), nil, nil,
False, NORMAL_PRIORITY_CLASS,
nil, nil, LStartupInfo, LProcessInfo) then
begin
repeat
LWaitResult := WaitForSingleObject(LProcessInfo.hProcess, 500);
// do something, like update a GUI or call Application.ProcessMessages
until LWaitResult <> WAIT_TIMEOUT;
result := LWaitResult = WAIT_OBJECT_0;
GetExitCodeProcess(LProcessInfo.hProcess, VProcessResult);
CloseHandle(LProcessInfo.hProcess);
CloseHandle(LProcessInfo.hThread);
end;
end;
After ExecAndWait returns, then you can sleep for 100ms if you need to.
N#

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