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Capturing all of the Output from a Console application
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Title: Capturing all of the Output from a Console application
Question: Use the function GetDosOutput in your application to capture all the output from a DOS application (this version only supports 32-bit console applications for how to do this with 16 bit see the update to this article http://www.delphi3000.com/articles/article_2298.asp).
Code recieved from Mike Lischke (Team JEDI) in response to a question I asked on the borland winapi newsgroup. It came from his app "Compiler Generator" (www.lischke-online.de/DCG.html) and then was converted to the GetDosOutput function by me. You can contact me at johnwlong@characterlink.net.
Answer:
unit consoleoutput;
interface
uses
Controls, Windows, SysUtils, Forms;
function GetDosOutput(const CommandLine:string): string;
implementation
function GetDosOutput(const CommandLine:string): string;
var
SA: TSecurityAttributes;
SI: TStartupInfo;
PI: TProcessInformation;
StdOutPipeRead, StdOutPipeWrite: THandle;
WasOK: Boolean;
Buffer: array[0..255] of Char;
BytesRead: Cardinal;
WorkDir, Line: String;
begin
Application.ProcessMessages;
with SA do
begin
nLength := SizeOf(SA);
bInheritHandle := True;
lpSecurityDescriptor := nil;
end;
// create pipe for standard output redirection
CreatePipe(StdOutPipeRead, // read handle
StdOutPipeWrite, // write handle
@SA, // security attributes
0 // number of bytes reserved for pipe - 0
default
);
try
// Make child process use StdOutPipeWrite as standard out,
// and make sure it does not show on screen.
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 std
input
hStdOutput := StdOutPipeWrite;
hStdError := StdOutPipeWrite;
end;
// launch the command line compiler
WorkDir := ExtractFilePath(CommandLine);
WasOK := CreateProcess(nil, PChar(CommandLine), nil, nil, True, 0, nil,
PChar(WorkDir), SI, PI);
// Now that the handle has been inherited, close write to be safe.
// We don't want to read or write to it accidentally.
CloseHandle(StdOutPipeWrite);
// if process could be created then handle its output
if not WasOK then
raise Exception.Create('Could not execute command line!')
else
try
// get all output until dos app finishes
Line := '';
repeat
// read block of characters (might contain carriage returns and
line feeds)
WasOK := ReadFile(StdOutPipeRead, Buffer, 255, BytesRead, nil);
// has anything been read?
if BytesRead 0 then
begin
// finish buffer to PChar
Buffer[BytesRead] := #0;
// combine the buffer with the rest of the last run
Line := Line + Buffer;
end;
until not WasOK or (BytesRead = 0);
// wait for console app to finish (should be already at this point)
WaitForSingleObject(PI.hProcess, INFINITE);
finally
// Close all remaining handles
CloseHandle(PI.hThread);
CloseHandle(PI.hProcess);
end;
finally
result:=Line;
CloseHandle(StdOutPipeRead);
end;
end;
end.
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