Problem/Question/Abstract:
Does anyone have a working example of a GUI application that redirects the screen output from a console application? I've tried it using the CreateProcess API function, however it only works for me when I launch it through the D5 UI, but not when I double click the compiled executable.
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 stdinput}
hStdOutput := StdOutPipeWrite;
hStdError := StdOutPipeWrite;
end;
{launch the command line compiler
WorkDir := 'C:\';}
WorkDir := '';
WasOK := CreateProcess(nil, PChar(CommandLine), nil, nil, True, 0, nil, nil, 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.
收藏
推荐
评论加载中…
