In my answer to this question, where the asker needed a fast way to get a directory listing of a folder on a network drive, I suggested using the DOS "dir" command. Unfortunately, it's a command, not a program, so you can't execute it with CreateProcess and so I had to put it in a batch file. I don't really like that solution. It feels like a hack to me. Does anyone know a way to run dir from Delphi instead of from an external batch file?
Invisible Solution (Create a pipe, execute the command, redirect stdout to the pipe, read out the pipe):
function Console(const Command: String): String;
var
StartupInfo: TStartupInfo;
ProcessInfo: TProcessInformation;
SecurityAttr: TSecurityAttributes;
OutputPipeRead, OutputPipeWrite: THandle;
Res: Boolean;
BufSize: Cardinal;
Buffer: String;
BytesRead: Cardinal;
begin
FillChar(ProcessInfo, SizeOf(TProcessInformation), 0);
FillChar(SecurityAttr, SizeOf(TSecurityAttributes), 0);
SecurityAttr.nLength := SizeOf(SecurityAttr);
SecurityAttr.bInheritHandle := true;
SecurityAttr.lpSecurityDescriptor := nil;
CreatePipe(OutputPipeRead, OutputPipeWrite, #SecurityAttr, 0);
FillChar(StartupInfo, SizeOf(TStartupInfo), 0);
StartupInfo.cb:=SizeOf(StartupInfo);
StartupInfo.hStdInput := 0;
StartupInfo.hStdOutput := OutputPipeWrite;
StartupInfo.hStdError := OutputPipeWrite;
StartupInfo.wShowWindow := SW_HIDE;
StartupInfo.dwFlags := STARTF_USESHOWWINDOW or STARTF_USESTDHANDLES;
Res := CreateProcess(nil, PChar(command), nil, nil, true,
CREATE_DEFAULT_ERROR_MODE or CREATE_NEW_CONSOLE or
NORMAL_PRIORITY_CLASS, nil, nil, StartupInfo, ProcessInfo);
CloseHandle(OutputPipeWrite);
Result := '';
if Res then
begin
SetLength(Buffer, 5000);
BufSize := Length(Buffer);
repeat
Res := ReadFile(OutputPipeRead, Buffer[1], BufSize, BytesRead, nil);
Result := Result + Copy(Buffer, 1, BytesRead);
until not Res;
WaitForSingleObject(ProcessInfo.hProcess, INFINITE);
CloseHandle(ProcessInfo.hProcess);
end;
CloseHandle(OutputPipeRead);
end;
Sample Usage:
ShowMessage(Console('cmd /c dir C:\'));
You don't need a batch file, you can just execute:
cmd.exe /c dir
You can check the option to command with cmd /?:
c:> cmd /?
CMD [/A | /U] [/Q] [/D] [/E:ON | /E:OFF] [/F:ON | /F:OFF] [/V:ON | /V:OFF]
[[/S] [/C | /K] string]
/C Carries out the command specified by string and then terminates
: : : : :
Why not FindFirstFile? It returns an attribute for each item that you can compare with FILE_ATTRIBUTE_DIRECTORY to check for a directory. I highly suspect that dir doesn't do anything else.
Using the dir command is like using a bar to type on the keyboard.
Using DSiWin32:
sl := TStringList.Create;
if DSiExecuteAndCapture('cmd.exe /c dir', sl, 'c:\test', exitCode) = 0 then
// exec error
else
// use sl
sl.Free;
Related
I wrote a console application that is able to execute multiple commands on the command line in parallel.
Primarily I did this out of interest and because the build processes of the software projects I am working on make excessive use of the command line.
Currently, before I create a child process in a worker thread, I create an anonymous pipe in order to capture all the output the child process creates during its lifetime.
After the child process terminates, the worker thread pushes the captured content to the waiting main process that then prints it out.
Here's my process creations and capturing:
procedure ReadPipe(const ReadHandle: THandle; const Output: TStream);
var
Buffer: TMemoryStream;
BytesRead, BytesToRead: DWord;
begin
Buffer := TMemoryStream.Create;
try
BytesRead := 0;
BytesToRead := 0;
if PeekNamedPipe(ReadHandle, nil, 0, nil, #BytesToRead, nil) then
begin
if BytesToRead > 0 then
begin
Buffer.Size := BytesToRead;
ReadFile(ReadHandle, Buffer.Memory^, Buffer.Size, BytesRead, nil);
if Buffer.Size <> BytesRead then
begin
Buffer.Size := BytesRead;
end;
if Buffer.Size > 0 then
begin
Output.Size := Output.Size + Buffer.Size;
Output.WriteBuffer(Buffer.Memory^, Buffer.Size);
end;
end;
end;
finally
Buffer.Free;
end;
end;
function CreateProcessWithRedirectedOutput(const AppName, CMD, DefaultDir: PChar; out CapturedOutput: String): Cardinal;
const
TIMEOUT_UNTIL_NEXT_PIPEREAD = 100;
var
SecurityAttributes: TSecurityAttributes;
ReadHandle, WriteHandle: THandle;
StartupInfo: TStartupInfo;
ProcessInformation: TProcessInformation;
ProcessStatus: Cardinal;
Output: TStringStream;
begin
Result := 0;
CapturedOutput := '';
Output := TStringStream.Create;
try
SecurityAttributes.nLength := SizeOf(SecurityAttributes);
SecurityAttributes.lpSecurityDescriptor := nil;
SecurityAttributes.bInheritHandle := True;
if CreatePipe(ReadHandle, WriteHandle, #SecurityAttributes, 0) then
begin
try
FillChar(StartupInfo, Sizeof(StartupInfo), 0);
StartupInfo.cb := SizeOf(StartupInfo);
StartupInfo.hStdOutput := WriteHandle;
StartupInfo.hStdError := WriteHandle;
StartupInfo.hStdInput := GetStdHandle(STD_INPUT_HANDLE);
StartupInfo.dwFlags := STARTF_USESTDHANDLES;
if CreateProcess(AppName, CMD,
#SecurityAttributes, #SecurityAttributes,
True, NORMAL_PRIORITY_CLASS,
nil, DefaultDir,
StartupInfo, ProcessInformation)
then
begin
try
repeat
ProcessStatus := WaitForSingleObject(ProcessInformation.hProcess, TIMEOUT_UNTIL_NEXT_PIPEREAD);
ReadPipe(ReadHandle, Output);
until ProcessStatus <> WAIT_TIMEOUT;
if not Windows.GetExitCodeProcess(ProcessInformation.hProcess, Result) then
begin
Result := GetLastError;
end;
finally
Windows.CloseHandle(ProcessInformation.hProcess);
Windows.CloseHandle(ProcessInformation.hThread);
end;
end
else
begin
Result := GetLastError;
end;
finally
Windows.CloseHandle(ReadHandle);
Windows.CloseHandle(WriteHandle);
end;
end
else
begin
Result := GetLastError;
end;
CapturedOutput := Output.DataString;
finally
Output.Free;
end;
end;
My problem now:
This method doesn't preserve potential coloring of the captured output!
I came accross this topic Capture coloured console output into WPF application but that didn't help me out, as I don't receive any color data through the anonymous pipe, just plain old text.
I experimented with inheriting the console of the main process to the child processes via CreateFile with 'CONOUT$', but while the colors are indeed preserved, you probably can guess that its pure mayhem if more than one process prints out its contents into one and the same console.
My next approach was to create additional console buffers with CreateConsoleScreenBuffer for each child process and read the contents with ReadConsole, but that wasn't successful as ReadConsole returns with System Error 6 (ERROR_INVALID_HANDLE).
ConsoleHandle := CreateConsoleScreenBuffer(
GENERIC_READ or GENERIC_WRITE,
FILE_SHARE_READ or FILE_SHARE_WRITE,
#SecurityAttributes,
CONSOLE_TEXTMODE_BUFFER,
nil);
//...
StartupInfo.hStdOutput := ConsoleHandle;
StartupInfo.hStdError := ConsoleHandle;
//...
ConsoleOutput := TMemoryStream.Create
ConsoleOutput.Size := MAXWORD;
ConsoleOutput.Position := 0;
ReadConsole(ConsoleHandle, ConsoleOutput.Memory, ConsoleOutput.Size, CharsRead, nil) // Doesn't read anything and returns with System Error Code 6.
I also read up on virtual terminal sequences and AllocConsole, AttachConsole and FreeConsole, but can't quite wrap my head around it for my use case.
What is the right/best way to preserve/receive coloring information of the console output of a child process?
I was on the right track with CreateConsoleScreenBuffer and giving each thread its own console screen buffer.
The problem was ReadConsole which doesn't do what I expected.
I now got it working with ReadConsoleOutput.
It should be noted however, that this method is the legacy way of doing it.
If you want to do it the "new way" you should probably use Pseudo Console Sessions.
Its support starts with Windows 10 1809 and Windows Server 2019.
It should also be noted, that the method of reading the output of a process/program via console screen buffer has its flaws and two distinct disadvantages compared to anonymous pipes:
The console screen buffer can't get full and block the process/program, but if the end of it is reached, new lines will push the current first line out of the buffer.
Output from processes/programs that spam their std output in a fast fashion will most likely lead to loss of information, as you won't be able to read, clear and move the cursor in the console screen buffer fast enough.
I try to circumvent both by increasing the console screen buffers y size component to its maximum possible size (I found it to be MAXSHORT - 1) and just wait until the process/program has finished.
That's good enough for me, as I don't need to analyze or process the colored output, but just display it in a console window, which is itself limited to MAXSHORT - 1 lines.
In every other scenario I will be using pipes and advise everyone else to do so too!
Here is a short version without any error handling that can be executed in parallel without interference (provided the TStream object is owned by the thread or thread-safe):
procedure CreateProcessWithConsoleCapture(const aAppName, aCMD, aDefaultDir: PChar;
const CapturedOutput: TStream);
const
CONSOLE_SCREEN_BUFFER_SIZE_Y = MAXSHORT - 1;
var
SecurityAttributes: TSecurityAttributes;
ConsoleHandle: THandle;
StartupInfo: TStartupInfo;
ProcessInformation: TProcessInformation;
CharsRead: Cardinal;
BufferSize, Origin: TCoord;
ConsoleScreenBufferInfo: TConsoleScreenBufferInfo;
Buffer: array of TCharInfo;
ReadRec: TSmallRect;
begin
SecurityAttributes.nLength := SizeOf(SecurityAttributes);
SecurityAttributes.lpSecurityDescriptor := Nil;
SecurityAttributes.bInheritHandle := True;
ConsoleHandle := CreateConsoleScreenBuffer(
GENERIC_READ or GENERIC_WRITE,
FILE_SHARE_READ or FILE_SHARE_WRITE,
#SecurityAttributes,
CONSOLE_TEXTMODE_BUFFER,
nil);
try
GetConsoleScreenBufferInfo(ConsoleHandle, ConsoleScreenBufferInfo);
BufferSize.X := ConsoleScreenBufferInfo.dwSize.X;
BufferSize.Y := CONSOLE_SCREEN_BUFFER_SIZE_Y;
SetConsoleScreenBufferSize(ConsoleHandle, BufferSize);
Origin.X := 0;
Origin.Y := 0;
FillConsoleOutputCharacter(ConsoleHandle, #0, BufferSize.X * BufferSize.Y, Origin, CharsRead);
SetStdHandle(STD_OUTPUT_HANDLE, ConsoleHandle);
FillChar(StartupInfo, Sizeof(StartupInfo), 0);
StartupInfo.cb := SizeOf(StartupInfo);
StartupInfo.hStdOutput := ConsoleHandle;
StartupInfo.hStdError := ConsoleHandle;
StartupInfo.hStdInput := GetStdHandle(STD_INPUT_HANDLE);
StartupInfo.dwFlags := STARTF_USESTDHANDLES or STARTF_FORCEOFFFEEDBACK;
CreateProcess(aAppName, aCMD,
#SecurityAttributes, #SecurityAttributes,
True, NORMAL_PRIORITY_CLASS,
nil, aDefaultDir,
StartupInfo, ProcessInformation);
try
WaitForSingleObject(ProcessInformation.hProcess, INFINITE);
GetConsoleScreenBufferInfo(ConsoleHandle, ConsoleScreenBufferInfo);
BufferSize.X := ConsoleScreenBufferInfo.dwSize.X;
BufferSize.Y := ConsoleScreenBufferInfo.dwCursorPosition.Y;
if ConsoleScreenBufferInfo.dwCursorPosition.X > 0 then
begin
Inc(BufferSize.Y);
end;
ReadRec.Left := 0;
ReadRec.Top := 0;
ReadRec.Right := BufferSize.X - 1;
ReadRec.Bottom := BufferSize.Y - 1;
SetLength(Buffer, BufferSize.X * BufferSize.Y);
ReadConsoleOutput(ConsoleHandle, #Buffer[0], BufferSize, Origin, ReadRec);
CharsRead := SizeOf(TCharInfo) * (ReadRec.Right - ReadRec.Left + 1) * (ReadRec.Bottom - ReadRec.Top + 1);
if CharsRead > 0 then
begin
CapturedOutput.Size := CapturedOutput.Size + CharsRead;
CapturedOutput.WriteBuffer(Buffer[0], CharsRead);
end;
finally
CloseHandle(ProcessInformation.hProcess);
CloseHandle(ProcessInformation.hThread);
end;
finally
CloseHandle(ConsoleHandle);
end;
end;
I would like to start one cmd process and keep feeding it some different commands. I would like to get every text cmd output as soon as text is out. So far I have this:
function GetDosOutput(const ACommandLine: string;
AWorkDir: string = 'C:\'): string;
var
_SA: TSecurityAttributes;
_SI: TStartupInfo;
_PI: TProcessInformation;
_StdOutPipeRead, StdOutPipeWrite: THandle;
_WasOK: boolean;
_Buffer: array [0 .. 255] of AnsiChar;
_BytesRead: Cardinal;
_Handle: boolean;
begin
Result := '';
_SA.nLength := SizeOf(_SA);
_SA.bInheritHandle := True;
_SA.lpSecurityDescriptor := nil;
CreatePipe(_StdOutPipeRead, StdOutPipeWrite, #_SA, 0);
try
FillChar(_SI, SizeOf(_SI), 0);
_SI.cb := SizeOf(_SI);
_SI.dwFlags := STARTF_USESHOWWINDOW or STARTF_USESTDHANDLES;
_SI.wShowWindow := SW_HIDE;
_SI.hStdInput := GetStdHandle(STD_INPUT_HANDLE);
_SI.hStdOutput := StdOutPipeWrite;
_SI.hStdError := StdOutPipeWrite;
_Handle := CreateProcess(nil, PChar('cmd.exe /C ' + ACommandLine), nil, nil,
True, 0, nil, PChar(AWorkDir), _SI, _PI);
CloseHandle(StdOutPipeWrite);
if _Handle then
try
repeat
_WasOK := ReadFile(_StdOutPipeRead, _Buffer, 255, _BytesRead, nil);
if _BytesRead > 0 then
begin
_Buffer[_BytesRead] := #0;
Result := Result + string(_Buffer);
Application.ProcessMessages;
end;
until not _WasOK or (_BytesRead = 0);
WaitForSingleObject(_PI.hProcess, INFINITE);
finally
CloseHandle(_PI.hThread);
CloseHandle(_PI.hProcess);
end;
finally
CloseHandle(_StdOutPipeRead);
end;
end;
How do I keep same cmd.exe process and give it different commands, e.g.
1) ping stackoverflow.com, see its content as soon as one line is printed
2) ipconfig /all ?
How can I get Delphi to pass a string to the input pipe to a CMD process. I am able to get an error pipe and output pipe functioning properly, unfortunately not the input pipe. The code I am using is taken from an online tutorial for piping. There were several errors in the original code causing problems when it was compiled. They have been fixed but I am left with problems when trying to pass input still.
Here is the code in the Form.Create event. I also have included the WritePipe and ReadPipe methods. WritePipe does not work, ReadPipe does work. Both WriteFile and ReadFile in the Pipe methods return a successful message, only the ReadPipe actually works however.
var
DosApp: String;
DosSize: Integer;
Security : TSecurityAttributes;
start : TStartUpInfo;
byteswritten: DWord;
WriteString : ansistring;
begin
CommandText.Clear;
// get COMSPEC variable, this is the path of the command-interpreter
SetLength(Dosapp, 255);
DosSize := GetEnvironmentVariable('COMSPEC', #DosApp[1], 255);
SetLength(Dosapp, DosSize);
// create pipes
With Security do
begin
nlength := SizeOf(TSecurityAttributes) ;
binherithandle := true;
lpsecuritydescriptor := nil;
end;
CreatePipe(InputPipeRead, InputPipeWrite, #Security, 0);
CreatePipe(OutputPipeRead, OutputPipeWrite, #Security, 0);
CreatePipe(ErrorPipeRead, ErrorPipeWrite, #Security, 0);
// start command-interpreter
FillChar(Start,Sizeof(Start),#0) ;
//start.hStdInput := InputPipeRead;
start.hStdOutput := OutputPipeWrite;
start.hStdError := ErrorPipeWrite;
start.dwFlags := STARTF_USESTDHANDLES + STARTF_USESHOWWINDOW;
start.wShowWindow := SW_Show;//SW_HIDE;
start.cb := SizeOf(start) ;
if CreateProcess('', PChar(DosApp), #Security, #Security, true,
CREATE_NEW_CONSOLE or SYNCHRONIZE, // CREATE_NO_WINDOW,
nil, nil, start, ProcessInfo) then
begin
MyThread := MainUnit.monitor.Create; // start monitor thread
MyThread.Priority := tpHigher;
end;
Button1.Enabled := true;
cmdcount := 1;
end;
Write Pipe:
procedure WritePipeOut(OutputPipe: THandle; InString: PWideChar);
// writes Instring to the pipe handle described by OutputPipe
var
count : integer;
byteswritten: DWord;
outputstring : PAnsiChar;
TextBuffer: array[1..32767] of AnsiChar;// char;
TextString: String;
begin
// most console programs require CR/LF after their input.
InString := PWideChar(InString + #13#10);
WriteFile(InputPipeWrite, InString[1], Length(InString), byteswritten, nil);
end;
Read Pipe:
function ReadPipeInput(InputPipe: THandle; var BytesRem: Integer): String;
{
reads console output from InputPipe. Returns the input in function
result. Returns bytes of remaining information to BytesRem
}
var
TextBuffer: array[1..32767] of AnsiChar;// char;
TextString: String;
BytesRead: Cardinal;
PipeSize: Integer;
begin
Result := '';
PipeSize := length(TextBuffer);
// check if there is something to read in pipe
PeekNamedPipe(InputPipe, nil, PipeSize, #BytesRead, #PipeSize, #BytesRem);
if bytesread > 0 then
begin
ReadFile(InputPipe, TextBuffer, pipesize, bytesread, nil);
// a requirement for Windows OS system components
OemToChar(#TextBuffer, #TextBuffer);
TextString := String(TextBuffer);
SetLength(TextString, BytesRead);
Result := TextString;
end;
end;
Further note; this is for use with the Java Debugger, which requires input in stages and so I do not believe there is any alternative method other than manipulating input directly to the JDB.
Any help is much appreciated!
1) You should pass InputPipeRead as hStdInput into CreateProcess: uncomment your line start.hStdInput := InputPipeRead;
2) The WritePipeOut function has two errors: it writes a Unicode (UTF-16LE) string into a pipe, and it skips the first character (since it writes a memory area beginning at InString[1]). Instead of WriteFile(InputPipeWrite, InString[1], Length(InString),... you should write something like:
var AnsiBuf: AnsiString;
...
AnsiBuf := String(InString) + #13#10;
Write(InputPipeWrite, AnsiBuf[1], Length(AnsiBuf), byteswritten, nil);
I'm trying to follow this msdn article.
I created a very simple console app.
Writeln('Take a nap.');
Sleep(1000);
Writeln('Done.');
I'm using the following code to launch the console app and (try to) read its output. Both the console app and the main app hang.
procedure TForm1.Button1Click(Sender: TObject);
const
PATH: WideString = 'c:\tmp\nap.exe';
var
ProcInfo: TProcessInformation;
StartInfo: TStartupInfo;
WorkingDir: WideString;
StdOutRead, StdOutWrite: THandle;
Attr: SECURITY_ATTRIBUTES;
N: Cardinal;
Buf: Array [0.. 5000] of Byte;
begin
FillChar(Attr, SizeOf(SECURITY_ATTRIBUTES), 0);
Attr.nLength := SizeOf(SECURITY_ATTRIBUTES);
Attr.bInheritHandle := True;
Attr.lpSecurityDescriptor := nil;
if not (CreatePipe(StdOutRead, StdOutWrite, #Attr, 0)) then
RaiseLastOSError;
FillChar(StartInfo, SizeOf(TStartupInfo), 0);
StartInfo.cb := SizeOf(TStartupInfo);
StartInfo.dwFlags := STARTF_USESTDHANDLES;
StartInfo.hStdOutput := StdOutWrite;
// I've tried creating pipes for stdin and stderr to no avail
WorkingDir := ExtractFilePath(PATH);
if not CreateProcess(nil, PWideChar(PATH), nil, nil, false, 0, nil, PWideChar(WorkingDir), StartInfo, ProcInfo) then
RaiseLastOSError;
// this call hangs -- the console app hangs regardless
if not ReadFile(StdOutRead, Buf[0], Length(Buf), N, nil) then
RaiseLastOSError;
end;
Any suggestions... unfortunately this article didn't help either.
The most obvious flaw that I can see is that you set bInheritHandles to False when you call CreateProcess. You must pass True and when you do so your code works as expected. The output from nap.exe is faithfully read into Buf.
I have a commandline application coded in delphi that I need to call from a normal desktop application (also coded in delphi). In short, I want to call the commandline app and display the text it outputs "live" in a listbox.
It's been ages since I have played around with the shell, but I distinctly remember that in order to grab the text from a commandline app - I have to use the pipe symbol ">". Like this:
C:/mycmdapp.exe >c:/result.txt
This will take any text printed to the shell (using writeLn) and dump it to a textfile called "result.txt".
But.. (and here comes the pickle), I want a live result rather than a backlog file. A typical example is the Delphi compiler itself - which manages to report back to the IDE what is going on. If my memory serves me correctly, I seem to recall that I must create a "pipe" channel (?), and then assign the pipe-name to the shell call.
I have tried to google this but I honestly was unsure of how to formulate it. Hopefully someone from the community can point me in the right direction.
Updated: This question might be identical to How do I run a command-line program in Delphi?. Some of the answers fit what I'm looking for, although the title and question itself is not identical.
As ever so often Zarco Gajic has a solution: Capture the output from a DOS (command/console) Window. This is a copy from his article for future reference:
The example runs 'chkdsk.exe c:\' and displays the output to Memo1.
Put a TMemo (Memo1) and a TButton (Button1) on your form. Put this code in the OnCLick event procedure for Button1:
procedure RunDosInMemo(DosApp: string; AMemo:TMemo);
const
READ_BUFFER_SIZE = 2400;
var
Security: TSecurityAttributes;
readableEndOfPipe, writeableEndOfPipe: THandle;
start: TStartUpInfo;
ProcessInfo: TProcessInformation;
Buffer: PAnsiChar;
BytesRead: DWORD;
AppRunning: DWORD;
begin
Security.nLength := SizeOf(TSecurityAttributes);
Security.bInheritHandle := True;
Security.lpSecurityDescriptor := nil;
if CreatePipe({var}readableEndOfPipe, {var}writeableEndOfPipe, #Security, 0) then
begin
Buffer := AllocMem(READ_BUFFER_SIZE+1);
FillChar(Start, Sizeof(Start), #0);
start.cb := SizeOf(start);
// Set up members of the STARTUPINFO structure.
// This structure specifies the STDIN and STDOUT handles for redirection.
// - Redirect the output and error to the writeable end of our pipe.
// - We must still supply a valid StdInput handle (because we used STARTF_USESTDHANDLES to swear that all three handles will be valid)
start.dwFlags := start.dwFlags or STARTF_USESTDHANDLES;
start.hStdInput := GetStdHandle(STD_INPUT_HANDLE); //we're not redirecting stdInput; but we still have to give it a valid handle
start.hStdOutput := writeableEndOfPipe; //we give the writeable end of the pipe to the child process; we read from the readable end
start.hStdError := writeableEndOfPipe;
//We can also choose to say that the wShowWindow member contains a value.
//In our case we want to force the console window to be hidden.
start.dwFlags := start.dwFlags + STARTF_USESHOWWINDOW;
start.wShowWindow := SW_HIDE;
// Don't forget to set up members of the PROCESS_INFORMATION structure.
ProcessInfo := Default(TProcessInformation);
//WARNING: The unicode version of CreateProcess (CreateProcessW) can modify the command-line "DosApp" string.
//Therefore "DosApp" cannot be a pointer to read-only memory, or an ACCESS_VIOLATION will occur.
//We can ensure it's not read-only with the RTL function: UniqueString
UniqueString({var}DosApp);
if CreateProcess(nil, PChar(DosApp), nil, nil, True, NORMAL_PRIORITY_CLASS, nil, nil, start, {var}ProcessInfo) then
begin
//Wait for the application to terminate, as it writes it's output to the pipe.
//WARNING: If the console app outputs more than 2400 bytes (ReadBuffer),
//it will block on writing to the pipe and *never* close.
repeat
Apprunning := WaitForSingleObject(ProcessInfo.hProcess, 100);
Application.ProcessMessages;
until (Apprunning <> WAIT_TIMEOUT);
//Read the contents of the pipe out of the readable end
//WARNING: if the console app never writes anything to the StdOutput, then ReadFile will block and never return
repeat
BytesRead := 0;
ReadFile(readableEndOfPipe, Buffer[0], READ_BUFFER_SIZE, {var}BytesRead, nil);
Buffer[BytesRead]:= #0;
OemToAnsi(Buffer,Buffer);
AMemo.Text := AMemo.text + String(Buffer);
until (BytesRead < READ_BUFFER_SIZE);
end;
FreeMem(Buffer);
CloseHandle(ProcessInfo.hProcess);
CloseHandle(ProcessInfo.hThread);
CloseHandle(readableEndOfPipe);
CloseHandle(writeableEndOfPipe);
end;
end;
procedure TForm1.Button1Click(Sender: TObject);
begin {button 1 code}
RunDosInMemo('chkdsk.exe c:\',Memo1);
end;
Update:
The above example reads the output in one step. Here is another example from DelphiDabbler showing how the output can be read while the process is still running:
function GetDosOutput(CommandLine: string; Work: string = 'C:\'): string;
var
SA: TSecurityAttributes;
SI: TStartupInfo;
PI: TProcessInformation;
StdOutPipeRead, StdOutPipeWrite: THandle;
WasOK: Boolean;
Buffer: array[0..255] of AnsiChar;
BytesRead: Cardinal;
WorkDir: string;
Handle: Boolean;
begin
Result := '';
with SA do begin
nLength := SizeOf(SA);
bInheritHandle := True;
lpSecurityDescriptor := nil;
end;
CreatePipe(StdOutPipeRead, StdOutPipeWrite, #SA, 0);
try
with SI do
begin
FillChar(SI, SizeOf(SI), 0);
cb := SizeOf(SI);
dwFlags := STARTF_USESHOWWINDOW or STARTF_USESTDHANDLES;
wShowWindow := SW_HIDE;
hStdInput := GetStdHandle(STD_INPUT_HANDLE); // don't redirect stdin
hStdOutput := StdOutPipeWrite;
hStdError := StdOutPipeWrite;
end;
WorkDir := Work;
Handle := CreateProcess(nil, PChar('cmd.exe /C ' + CommandLine),
nil, nil, True, 0, nil,
PChar(WorkDir), SI, PI);
CloseHandle(StdOutPipeWrite);
if Handle then
try
repeat
WasOK := ReadFile(StdOutPipeRead, Buffer, 255, BytesRead, nil);
if BytesRead > 0 then
begin
Buffer[BytesRead] := #0;
Result := Result + Buffer;
end;
until not WasOK or (BytesRead = 0);
WaitForSingleObject(PI.hProcess, INFINITE);
finally
CloseHandle(PI.hThread);
CloseHandle(PI.hProcess);
end;
finally
CloseHandle(StdOutPipeRead);
end;
end;
You probably have the code on your harddisk already: the Execute function in the JclSysUtils unit of the JCL (JEDI Code Library) does what you need:
function Execute(const CommandLine: string; OutputLineCallback: TTextHandler;
RawOutput: Boolean = False; AbortPtr: PBoolean = nil): Cardinal;
You can supply it with a callback procedure:
TTextHandler = procedure(const Text: string) of object;
Did an answer too for better understanding:
{type TTextHandler =} procedure TTextHandlerQ(const aText: string);
begin
memo2.lines.add(atext);
end;
writeln(itoa(JExecute('cmd /C dir *.*',#TTextHandlerQ, true, false)));
You have to use /C then cmd /c is used to run commands in MS-DOS and terminate after command or process completion, otherwise it blocks output to memo.