I'm trying to create a dll with delphi, I set some file attributes but then I want to run a .exe file from the working directory. I tried to run the exe file with this code
ShellExecute(Handle, 'open', 'start.exe', nil, nil, SW_SHOWNORMAL);
But I get errors: Undeclared identifier 'Handle'.
Undeclared identifier 'SW_SHOWNORMAL'
What would be the best way to run the exe file ?
Be sure to add ShellApi to your Unit's uses clause.
uses ShellApi;
The first parameter can be 0 if the program doesn't have a windows handle.
ShellExecute(0, 'open', ('start.exe'), nil, nil, SW_SHOW);
The "Handle" parameter is not defined in your start.exe procedure
Procedure TForm1.StartEXE;
begin
ShellExecute(0, 'open', ('start.exe'), nil, nil, SW_SHOW);
end;
This will make it universally-accessible from any other function or procedure within your TForm1.
The errors you describe in the question are:
Undeclared identifier 'Handle'
Only you know which handle to pass. Either pass a handle to a form, or the Application object's handle, or perhaps even 0 if your application does not have a window handle to hand.
Undeclared identifier 'SW_SHOWNORMAL'
That symbol is defined in the Windows unit. You simply need to add that unit to your uses list.
Add the Windows unit to the implementation clause of your unit where this call is made and your program will compile. ALthough the CreateProcess function would be a better option in this case. Something like this (not tested and off the top of my head) :-
Procedure ExecNewProcess(Const ProgramName : String; pWait : Boolean);
Var
lOK : Boolean;
lStartInfo : TStartupInfo;
lProcInfo : TProcessInformation;
Begin
FillChar(lStartInfo, SizeOf(TStartupInfo), #0);
FillChar(lProcInfo, SizeOf(TProcessInformation), #0);
lStartInfo.cb := SizeOf(TStartupInfo);
lOK := CreateProcess(Nil, PChar(ProgramName), Nil, Nil, False,
CREATE_NEW_PROCESS_GROUP + NORMAL_PRIORITY_CLASS, Nil, Nil, lStartInfo, lProcInfo);
If lOK Then
Begin
If pWait Then
WaitForSingleObject(lProcInfo.hProcess, INFINITE);
End
Else
ShowMessage('Unable to run ' + ProgramName);
CloseHandle(lProcInfo.hProcess);
CloseHandle(lProcInfo.hThread);
End;
lProcInfo is an out parameter; hence no need to initialise it. What's more, the second parameter of CreateProcess must be a modifiable string. You get away with it in D7 because you call the ANSI API which happens to let you off, but it's best practise to pass a modifiable string.CreateProcessW uses the buffer you provide as its workspace for parsing the string. You get away with it in CreateProcessA because that is a wrapper around CreateProcessW and CreateProcessA creates a modifiable buffer to pass to CreateProcessW. That's all implementation detail though, and the docs are clear. It's a very common mistake. Results in AV when you call the Unicode version. Copy the string to a local variable and call UniqueString on it. Job done.