我需要知道标准输入和标准输出是否已被重定向使用最新的FPC(V3.0.0)如何检测stdin或stdout是否在Windows下的FreePascal中重定向?
一个控制台应用程序在旧Turbo Pascal的日子里,我不得不写在组件这样做的功能。如下所示:
{ **************************************************************
* Routine : RedirectedStd *
* Purpose : Return Yes (True) if standard handle is being *
* : redirected. *
* Note(s) : Even though handle can take any handle value, *
* : the function will be meaningful only for the *
* : standard input, standard output, and standard *
* : error. It will, however, be True for any *
* : handle that does NOT point to the console. *
* : (Besides, this is what it actually checks for.)*
* : Make sure handle belongs to an open file or *
* : you will get wrong answer (check IOResult). *
************************************************************** }
function RedirectedStd(handle: Word): Boolean; assembler;
const
DEVICE = $0080;
FASTCONSOLE = $0010;
CONSOUT = $0002;
CONSIN = $0001;
asm
mov InOutRes,0
mov ax,$4400 { IOCTL svc, get device information }
mov bx,handle
int $21 { result in DX }
mov ax,1 { assume function is True }
jc @Error { got error with code in AX }
test dx,DEVICE
jz @Out
test dx,FASTCONSOLE
jz @Out
test dx,CONSOUT
jz @Out
test dx,CONSIN
jz @Out
xor ax,ax { function is False }
jmp @Out
@Error:
mov InOutRes,ax
@Out:
end; { RedirectedStd }
此语法对于FPC汇编器无效。我想我的运气有以下变体,它虽然编译OK崩溃:(不知道如果我的转换等效)
function RedirectedStd(handle: Word): Boolean; assembler;
label Error,Done;
const DEVICE = $0080;
FASTCONSOLE = $0010;
CONSOUT = $0002;
CONSIN = $0001;
asm
movw $0,InOutRes
movw $4400,%ax { IOCTL svc, get device information }
movw handle,%bx
int $21 { result in DX }
movw $1,%ax { assume function is True }
jc Error { got error with code in AX }
test DEVICE,%dx
jz Done
test FASTCONSOLE,%dx
jz Done
test CONSOUT,%dx
jz Done
test CONSIN,%dx
jz Done
xor %ax,%ax { function is False }
jmp Done
Error: movw %ax,InOutRes
Done:
end; { RedirectedStd }
任何想法?
编辑: 基于这给了我足够的方向找出解决办法接受的答案,我想出了下面的下拉更换为我原来的子程序:
function RedirectedStd(handle: Word): Boolean; {$ifndef WINDOWS} unimplemented; {$endif}
begin
RedirectedStd := False;
{$ifdef WINDOWS}
case handle of
0: RedirectedStd := GetFileType(GetStdHandle(STD_INPUT_HANDLE)) <> FILE_TYPE_CHAR;
1: RedirectedStd := GetFileType(GetStdHandle(STD_OUTPUT_HANDLE)) <> FILE_TYPE_CHAR;
2: RedirectedStd := GetFileType(GetStdHandle(STD_ERROR_HANDLE)) <> FILE_TYPE_CHAR;
end;
{$endif}
end; { RedirectedStd }
哦,你需要请使用Windows;
可能重复[如何确定Console.Out是否已被重定向到文件?](http://stackoverflow.com/questions/743885/how-can-i-determine-whether-console-out-已被重定向到一个文件) –
@DavidHeffernan:不是。我正在寻找FreePascal解决方案。 – tonypdmtr
在顶级答案中调用winapi函数。或者找到其中一个说无数其他的模糊的东西。这里有一个http://stackoverflow.com/questions/9021916/how-do-i-check-if-my-delphi-console-app-is-redirected-to-a-file-or-pipe还有很多很多 –