为什么我不能重定向 WriteConsole 的输出？
Why can't I redirect output from WriteConsole?
在下面的程序中，我使用两种不同的函数打印到控制台
#include <windows.h>
int main() {
HANDLE h = GetStdHandle(STD_OUTPUT_HANDLE);
DWORD byteswritten;
WriteConsole(h, "WriteConsole", 12, &byteswritten, NULL);
WriteFile(h, "WriteFile", 9, &byteswritten, NULL);
}
如果当我执行这个程序并使用 a > out.txt 或 a 1> out.txt 重定向它的输出时，没有任何内容打印到控制台（如预期的那样），但是 out.txt 的内容只是
WriteFile
两者之间的区别是允许对 WriteFile 的调用被重定向到文件并允许对 WriteConsole 的调用转到...无处
在 windows 10
上使用 gcc 和 msvc 进行了测试
WriteConsole 仅适用于控制台屏幕句柄，不适用于文件或管道。
如果您只编写 ASCII 内容，您可以使用 WriteFile 来编写所有内容。
如果您需要编写 Unicode 字符，您可以使用 GetConsoleMode 来检测句柄类型，对于不是控制台句柄的所有内容，它都会失败。
像这样进行原始输出时，如果句柄被重定向到文件，您还必须处理 BOM。
This blog post 是在 Windows 控制台中处理 Unicode 的良好起点...
如果对方使用WriteConsole，下面的代码可以用来重定向控制台输出。该代码通过隐藏的控制台屏幕缓冲区读取输出。我已经编写了这段代码来拦截一些 directshow 驱动程序写入控制台的调试输出。 Directshow 驱动程序有做驱动程序不应该做的事情的习惯，比如写入不需要的日志文件、写入控制台和崩溃。
// info to redirected console output
typedef struct tagRedConInfo
{
// hidden console
HANDLE hCon;
// old console handles
HANDLE hOldConOut;
HANDLE hOldConErr;
// buffer to read screen content
CHAR_INFO *BufData;
INT BufSize;
//
} TRedConInfo;
//------------------------------------------------------------------------------
// GLOBALS
//------------------------------------------------------------------------------
// initial handles
HANDLE gv_hOldConOut;
HANDLE gv_hOldConErr;
//------------------------------------------------------------------------------
// PROTOTYPES
//------------------------------------------------------------------------------
/* init redirecting the console output */
BOOL Shell_InitRedirectConsole(BOOL,TRedConInfo*);
/* done redirecting the console output */
BOOL Shell_DoneRedirectConsole(TRedConInfo*);
/* read string from hidden console, then clear */
BOOL Shell_ReadRedirectConsole(TRedConInfo*,TCHAR*,INT);
/* clear buffer of hidden console */
BOOL Shell_ClearRedirectConsole(TRedConInfo*);
//------------------------------------------------------------------------------
// IMPLEMENTATIONS
//------------------------------------------------------------------------------
/***************************************/
/* init redirecting the console output */
/***************************************/
BOOL Shell_InitRedirectConsole(BOOL in_SetStdHandles, TRedConInfo *out_RcInfo)
{
/* locals */
HANDLE lv_hCon;
SECURITY_ATTRIBUTES lv_SecAttr;
// preclear structure
memset(out_RcInfo, 0, sizeof(TRedConInfo));
// prepare inheritable handle just in case an api spans an external process
memset(&lv_SecAttr, 0, sizeof(SECURITY_ATTRIBUTES));
lv_SecAttr.nLength = sizeof(SECURITY_ATTRIBUTES);
lv_SecAttr.bInheritHandle = TRUE;
// create hidden console buffer
lv_hCon = CreateConsoleScreenBuffer(
GENERIC_READ|GENERIC_WRITE, FILE_SHARE_READ|FILE_SHARE_WRITE,
&lv_SecAttr, CONSOLE_TEXTMODE_BUFFER, 0);
// failed to create console buffer?
if (lv_hCon == INVALID_HANDLE_VALUE)
return FALSE;
// store
out_RcInfo->hCon = lv_hCon;
// set as standard handles for own process?
if (in_SetStdHandles)
{
// mutex the globals
WaitForGlobalVarMutex();
// remember the old handles
out_RcInfo->hOldConOut = GetStdHandle(STD_OUTPUT_HANDLE);
out_RcInfo->hOldConErr = GetStdHandle(STD_ERROR_HANDLE);
// set hidden console as std output
SetStdHandle(STD_OUTPUT_HANDLE, lv_hCon);
SetStdHandle(STD_ERROR_HANDLE, lv_hCon);
// is this the first instance?
if (!gv_hOldConOut)
{
// inform our own console output code about the old handles so our own
// console will be writing to the real console, only console output from
// other parties will write to the hidden console
gv_hOldConOut = out_RcInfo->hOldConOut;
gv_hOldConErr = out_RcInfo->hOldConErr;
}
// release mutex
ReleaseGlobalVarMutex();
}
// done
return TRUE;
}
/***************************************/
/* done redirecting the console output */
/***************************************/
BOOL Shell_DoneRedirectConsole(TRedConInfo *in_RcInfo)
{
// validate
if (!in_RcInfo->hCon)
return FALSE;
// restore original handles?
if (in_RcInfo->hOldConOut)
{
// mutex the globals
WaitForGlobalVarMutex();
// restore original handles
SetStdHandle(STD_OUTPUT_HANDLE, in_RcInfo->hOldConOut);
SetStdHandle(STD_ERROR_HANDLE, in_RcInfo->hOldConErr);
// was this the first instance?
if (in_RcInfo->hOldConOut == gv_hOldConOut)
{
// clear
gv_hOldConOut = NULL;
gv_hOldConErr = NULL;
}
// release mutex
ReleaseGlobalVarMutex();
}
// close the console handle
CloseHandle(in_RcInfo->hCon);
// free read buffer
if (in_RcInfo->BufData)
MemFree(in_RcInfo->BufData);
// clear structure
memset(in_RcInfo, 0, sizeof(TRedConInfo));
// done
return TRUE;
}
/***********************************************/
/* read string from hidden console, then clear */
/***********************************************/
BOOL Shell_ReadRedirectConsole(TRedConInfo *in_RcInfo, TCHAR *out_Str, INT in_MaxLen)
{
/* locals */
TCHAR lv_C;
INT lv_X;
INT lv_Y;
INT lv_W;
INT lv_H;
INT lv_N;
INT lv_Len;
INT lv_Size;
INT lv_PrvLen;
COORD lv_DstSze;
COORD lv_DstOfs;
DWORD lv_Written;
SMALL_RECT lv_SrcRect;
CHAR_INFO *lv_BufData;
CONSOLE_SCREEN_BUFFER_INFO lv_Info;
// preclear output
out_Str[0] = 0;
// validate
if (!in_RcInfo->hCon)
return FALSE;
// reserve character for eos
--in_MaxLen;
// get current buffer info
if (!GetConsoleScreenBufferInfo(in_RcInfo->hCon, &lv_Info))
return FALSE;
// check whether there is something at all
if (!lv_Info.dwSize.X || !lv_Info.dwSize.Y)
return FALSE;
// limit the buffer passed onto read call otherwise it
// will fail with out-of-resources error
lv_DstSze.X = (INT16)(lv_Info.dwSize.X);
lv_DstSze.Y = (INT16)(lv_Info.dwSize.Y < 8 ? lv_Info.dwSize.Y : 8);
// size of buffer needed
lv_Size = lv_DstSze.X * lv_DstSze.Y * sizeof(CHAR_INFO);
// is previous buffer too small?
if (!in_RcInfo->BufData || in_RcInfo->BufSize < lv_Size)
{
// free old buffer
if (in_RcInfo->BufData)
MemFree(in_RcInfo->BufData);
// allocate read buffer
if ((in_RcInfo->BufData = (CHAR_INFO*)MemAlloc(lv_Size)) == NULL)
return FALSE;
// store new size
in_RcInfo->BufSize = lv_Size;
}
// always write to (0,0) in buffer
lv_DstOfs.X = 0;
lv_DstOfs.Y = 0;
// init src rectangle
lv_SrcRect.Left = 0;
lv_SrcRect.Top = 0;
lv_SrcRect.Right = lv_DstSze.X;
lv_SrcRect.Bottom = lv_DstSze.Y;
// buffer to local
lv_BufData = in_RcInfo->BufData;
// start at first string position in output
lv_Len = 0;
// loop until no more rows to read
do
{
// read buffer load
if (!ReadConsoleOutput(in_RcInfo->hCon, lv_BufData, lv_DstSze, lv_DstOfs, &lv_SrcRect))
return FALSE;
// w/h of actually read content
lv_W = lv_SrcRect.Right - lv_SrcRect.Left + 1;
lv_H = lv_SrcRect.Bottom - lv_SrcRect.Top + 1;
// remember previous position
lv_PrvLen = lv_Len;
// loop through rows of buffer
for (lv_Y = 0; lv_Y < lv_H; ++lv_Y)
{
// reset output position of current row
lv_N = 0;
// loop through columns
for (lv_X = 0; lv_X < lv_W; ++lv_X)
{
// is output full?
if (lv_Len + lv_N > in_MaxLen)
break;
// get character from screen buffer, ignore attributes
lv_C = lv_BufData[lv_Y * lv_DstSze.X + lv_X].Char.UnicodeChar;
// append character
out_Str[lv_Len + lv_N++] = lv_C;
}
// remove spaces at the end of the line
while (lv_N > 0 && out_Str[lv_Len+lv_N-1] == ' ')
--lv_N;
// if row was not blank
if (lv_N > 0)
{
// update output position
lv_Len += lv_N;
// is output not full?
if (lv_Len + 2 < in_MaxLen)
{
// append cr/lf
out_Str[lv_Len++] = '\r';
out_Str[lv_Len++] = '\n';
}
}
}
// update screen position
lv_SrcRect.Top = (INT16)(lv_SrcRect.Top + lv_H);
lv_SrcRect.Bottom = (INT16)(lv_SrcRect.Bottom + lv_H);
// until nothing is added or no more screen rows
} while (lv_PrvLen != lv_Len && lv_SrcRect.Bottom < lv_Info.dwSize.Y);
// remove last cr/lf
if (lv_Len > 2)
lv_Len -= 2;
// append eos
out_Str[lv_Len] = 0;
// total screen buffer size in characters
lv_Size = lv_Info.dwSize.X * lv_Info.dwSize.Y;
// clear the buffer with spaces
FillConsoleOutputCharacter(in_RcInfo->hCon, ' ', lv_Size, lv_DstOfs, &lv_Written);
// reset cursor position to (0,0)
SetConsoleCursorPosition(in_RcInfo->hCon, lv_DstOfs);
// done
return TRUE;
}
/**********************************/
/* clear buffer of hidden console */
/**********************************/
BOOL Shell_ClearRedirectConsole(TRedConInfo *in_RcInfo)
{
/* locals */
INT lv_Size;
COORD lv_ClrOfs;
DWORD lv_Written;
CONSOLE_SCREEN_BUFFER_INFO lv_Info;
// validate
if (!in_RcInfo->hCon)
return FALSE;
// get current buffer info
if (!GetConsoleScreenBufferInfo(in_RcInfo->hCon, &lv_Info))
return FALSE;
// clear from (0,0) onward
lv_ClrOfs.X = 0;
lv_ClrOfs.Y = 0;
// total screen buffer size in characters
lv_Size = lv_Info.dwSize.X * lv_Info.dwSize.Y;
// clear the buffer with spaces
FillConsoleOutputCharacter(in_RcInfo->hCon, ' ', lv_Size, lv_ClrOfs, &lv_Written);
// reset cursor position to (0,0)
SetConsoleCursorPosition(in_RcInfo->hCon, lv_ClrOfs);
// done
return TRUE;
}
编辑 2021 年：
Windows 10 现在有 ConPTY API（又名伪控制台），它基本上允许任何程序充当另一个程序的控制台，从而可以捕获直接写入的输出控制台。
这使我的原始答案对于支持 ConPTY 的 Windows 版本已过时。
原回答：
来自reference：
WriteConsole fails if it is used with a standard handle that is
redirected to a file. If an application processes multilingual output
that can be redirected, determine whether the output handle is a
console handle (one method is to call the GetConsoleMode function and
check whether it succeeds). If the handle is a console handle, call
WriteConsole. If the handle is not a console handle, the output is
redirected and you should call WriteFile to perform the I/O.
这仅适用于您控制要重定向的应用程序的源代码的情况。我最近不得不 重定向来自一个无条件调用 WriteConsole() 的闭源应用程序 的输出，因此它无法正常重定向。
读取控制台屏幕缓冲区（如 ) prooved to be unreliable, so I used Microsoft Detours library 所建议，挂钩目标进程中的 WriteConsole() API 并在必要时调用 WriteFile()。否则调用原始进程WriteConsole() 函数。
我根据Using Detours的例子创建了一个hook DLL:
#include <windows.h>
#include <detours.h>
// Target pointer for the uninstrumented WriteConsoleW API.
//
auto WriteConsoleW_orig = &WriteConsoleW;
// Detour function that replaces the WriteConsoleW API.
//
BOOL WINAPI WriteConsoleW_hooked(
_In_ HANDLE hConsoleOutput,
_In_ const VOID *lpBuffer,
_In_ DWORD nNumberOfCharsToWrite,
_Out_ LPDWORD lpNumberOfCharsWritten,
_Reserved_ LPVOID lpReserved
)
{
// Check if this actually is a console screen buffer handle.
DWORD mode;
if( GetConsoleMode( hConsoleOutput, &mode ) )
{
// Forward to the original WriteConsoleW() function.
return WriteConsoleW_orig( hConsoleOutput, lpBuffer, nNumberOfCharsToWrite, lpNumberOfCharsWritten, lpReserved );
}
else
{
// This is a redirected handle (e. g. a file or a pipe). We multiply with sizeof(WCHAR), because WriteFile()
// expects the number of bytes, but WriteConsoleW() gets passed the number of characters.
BOOL result = WriteFile( hConsoleOutput, lpBuffer, nNumberOfCharsToWrite * sizeof(WCHAR), lpNumberOfCharsWritten, nullptr );
// WriteFile() returns number of bytes written, but WriteConsoleW() has to return the number of characters written.
if( lpNumberOfCharsWritten )
*lpNumberOfCharsWritten /= sizeof(WCHAR);
return result;
}
}
// DllMain function attaches and detaches the WriteConsoleW_hooked detour to the
// WriteConsoleW target function. The WriteConsoleW target function is referred to
// through the WriteConsoleW_orig target pointer.
//
BOOL WINAPI DllMain(HINSTANCE hinst, DWORD dwReason, LPVOID reserved)
{
if (DetourIsHelperProcess()) {
return TRUE;
}
if (dwReason == DLL_PROCESS_ATTACH) {
DetourRestoreAfterWith();
DetourTransactionBegin();
DetourUpdateThread(GetCurrentThread());
DetourAttach(&(PVOID&)WriteConsoleW_orig, WriteConsoleW_hooked);
DetourTransactionCommit();
}
else if (dwReason == DLL_PROCESS_DETACH) {
DetourTransactionBegin();
DetourUpdateThread(GetCurrentThread());
DetourDetach(&(PVOID&)WriteConsoleW_orig, WriteConsoleW_hooked);
DetourTransactionCommit();
}
return TRUE;
}
注意：在WriteFile()分支我不写BOM（字节顺序标记），因为它并不总是需要的（例如当重定向到管道而不是文件或附加到现有文件时）。使用 DLL 将进程输出重定向到文件的应用程序可以在启动重定向进程之前自行编写 UTF-16 LE BOM。
目标进程是使用 DetourCreateProcessWithDllExW(), specifying the name of our hook DLL as argument for the lpDllName parameter. The other arguments are identical to how you create a redirected process via the CreateProcessW() API 创建的。我就不细说了，因为这些都有据可查。
在下面的程序中，我使用两种不同的函数打印到控制台
#include <windows.h>
int main() {
HANDLE h = GetStdHandle(STD_OUTPUT_HANDLE);
DWORD byteswritten;
WriteConsole(h, "WriteConsole", 12, &byteswritten, NULL);
WriteFile(h, "WriteFile", 9, &byteswritten, NULL);
}
如果当我执行这个程序并使用 a > out.txt 或 a 1> out.txt 重定向它的输出时，没有任何内容打印到控制台（如预期的那样），但是 out.txt 的内容只是
WriteFile
两者之间的区别是允许对 WriteFile 的调用被重定向到文件并允许对 WriteConsole 的调用转到...无处
在 windows 10
上使用 gcc 和 msvc 进行了测试WriteConsole 仅适用于控制台屏幕句柄，不适用于文件或管道。
如果您只编写 ASCII 内容，您可以使用 WriteFile 来编写所有内容。
如果您需要编写 Unicode 字符，您可以使用 GetConsoleMode 来检测句柄类型，对于不是控制台句柄的所有内容，它都会失败。
像这样进行原始输出时，如果句柄被重定向到文件，您还必须处理 BOM。
This blog post 是在 Windows 控制台中处理 Unicode 的良好起点...
如果对方使用WriteConsole，下面的代码可以用来重定向控制台输出。该代码通过隐藏的控制台屏幕缓冲区读取输出。我已经编写了这段代码来拦截一些 directshow 驱动程序写入控制台的调试输出。 Directshow 驱动程序有做驱动程序不应该做的事情的习惯，比如写入不需要的日志文件、写入控制台和崩溃。
// info to redirected console output
typedef struct tagRedConInfo
{
// hidden console
HANDLE hCon;
// old console handles
HANDLE hOldConOut;
HANDLE hOldConErr;
// buffer to read screen content
CHAR_INFO *BufData;
INT BufSize;
//
} TRedConInfo;
//------------------------------------------------------------------------------
// GLOBALS
//------------------------------------------------------------------------------
// initial handles
HANDLE gv_hOldConOut;
HANDLE gv_hOldConErr;
//------------------------------------------------------------------------------
// PROTOTYPES
//------------------------------------------------------------------------------
/* init redirecting the console output */
BOOL Shell_InitRedirectConsole(BOOL,TRedConInfo*);
/* done redirecting the console output */
BOOL Shell_DoneRedirectConsole(TRedConInfo*);
/* read string from hidden console, then clear */
BOOL Shell_ReadRedirectConsole(TRedConInfo*,TCHAR*,INT);
/* clear buffer of hidden console */
BOOL Shell_ClearRedirectConsole(TRedConInfo*);
//------------------------------------------------------------------------------
// IMPLEMENTATIONS
//------------------------------------------------------------------------------
/***************************************/
/* init redirecting the console output */
/***************************************/
BOOL Shell_InitRedirectConsole(BOOL in_SetStdHandles, TRedConInfo *out_RcInfo)
{
/* locals */
HANDLE lv_hCon;
SECURITY_ATTRIBUTES lv_SecAttr;
// preclear structure
memset(out_RcInfo, 0, sizeof(TRedConInfo));
// prepare inheritable handle just in case an api spans an external process
memset(&lv_SecAttr, 0, sizeof(SECURITY_ATTRIBUTES));
lv_SecAttr.nLength = sizeof(SECURITY_ATTRIBUTES);
lv_SecAttr.bInheritHandle = TRUE;
// create hidden console buffer
lv_hCon = CreateConsoleScreenBuffer(
GENERIC_READ|GENERIC_WRITE, FILE_SHARE_READ|FILE_SHARE_WRITE,
&lv_SecAttr, CONSOLE_TEXTMODE_BUFFER, 0);
// failed to create console buffer?
if (lv_hCon == INVALID_HANDLE_VALUE)
return FALSE;
// store
out_RcInfo->hCon = lv_hCon;
// set as standard handles for own process?
if (in_SetStdHandles)
{
// mutex the globals
WaitForGlobalVarMutex();
// remember the old handles
out_RcInfo->hOldConOut = GetStdHandle(STD_OUTPUT_HANDLE);
out_RcInfo->hOldConErr = GetStdHandle(STD_ERROR_HANDLE);
// set hidden console as std output
SetStdHandle(STD_OUTPUT_HANDLE, lv_hCon);
SetStdHandle(STD_ERROR_HANDLE, lv_hCon);
// is this the first instance?
if (!gv_hOldConOut)
{
// inform our own console output code about the old handles so our own
// console will be writing to the real console, only console output from
// other parties will write to the hidden console
gv_hOldConOut = out_RcInfo->hOldConOut;
gv_hOldConErr = out_RcInfo->hOldConErr;
}
// release mutex
ReleaseGlobalVarMutex();
}
// done
return TRUE;
}
/***************************************/
/* done redirecting the console output */
/***************************************/
BOOL Shell_DoneRedirectConsole(TRedConInfo *in_RcInfo)
{
// validate
if (!in_RcInfo->hCon)
return FALSE;
// restore original handles?
if (in_RcInfo->hOldConOut)
{
// mutex the globals
WaitForGlobalVarMutex();
// restore original handles
SetStdHandle(STD_OUTPUT_HANDLE, in_RcInfo->hOldConOut);
SetStdHandle(STD_ERROR_HANDLE, in_RcInfo->hOldConErr);
// was this the first instance?
if (in_RcInfo->hOldConOut == gv_hOldConOut)
{
// clear
gv_hOldConOut = NULL;
gv_hOldConErr = NULL;
}
// release mutex
ReleaseGlobalVarMutex();
}
// close the console handle
CloseHandle(in_RcInfo->hCon);
// free read buffer
if (in_RcInfo->BufData)
MemFree(in_RcInfo->BufData);
// clear structure
memset(in_RcInfo, 0, sizeof(TRedConInfo));
// done
return TRUE;
}
/***********************************************/
/* read string from hidden console, then clear */
/***********************************************/
BOOL Shell_ReadRedirectConsole(TRedConInfo *in_RcInfo, TCHAR *out_Str, INT in_MaxLen)
{
/* locals */
TCHAR lv_C;
INT lv_X;
INT lv_Y;
INT lv_W;
INT lv_H;
INT lv_N;
INT lv_Len;
INT lv_Size;
INT lv_PrvLen;
COORD lv_DstSze;
COORD lv_DstOfs;
DWORD lv_Written;
SMALL_RECT lv_SrcRect;
CHAR_INFO *lv_BufData;
CONSOLE_SCREEN_BUFFER_INFO lv_Info;
// preclear output
out_Str[0] = 0;
// validate
if (!in_RcInfo->hCon)
return FALSE;
// reserve character for eos
--in_MaxLen;
// get current buffer info
if (!GetConsoleScreenBufferInfo(in_RcInfo->hCon, &lv_Info))
return FALSE;
// check whether there is something at all
if (!lv_Info.dwSize.X || !lv_Info.dwSize.Y)
return FALSE;
// limit the buffer passed onto read call otherwise it
// will fail with out-of-resources error
lv_DstSze.X = (INT16)(lv_Info.dwSize.X);
lv_DstSze.Y = (INT16)(lv_Info.dwSize.Y < 8 ? lv_Info.dwSize.Y : 8);
// size of buffer needed
lv_Size = lv_DstSze.X * lv_DstSze.Y * sizeof(CHAR_INFO);
// is previous buffer too small?
if (!in_RcInfo->BufData || in_RcInfo->BufSize < lv_Size)
{
// free old buffer
if (in_RcInfo->BufData)
MemFree(in_RcInfo->BufData);
// allocate read buffer
if ((in_RcInfo->BufData = (CHAR_INFO*)MemAlloc(lv_Size)) == NULL)
return FALSE;
// store new size
in_RcInfo->BufSize = lv_Size;
}
// always write to (0,0) in buffer
lv_DstOfs.X = 0;
lv_DstOfs.Y = 0;
// init src rectangle
lv_SrcRect.Left = 0;
lv_SrcRect.Top = 0;
lv_SrcRect.Right = lv_DstSze.X;
lv_SrcRect.Bottom = lv_DstSze.Y;
// buffer to local
lv_BufData = in_RcInfo->BufData;
// start at first string position in output
lv_Len = 0;
// loop until no more rows to read
do
{
// read buffer load
if (!ReadConsoleOutput(in_RcInfo->hCon, lv_BufData, lv_DstSze, lv_DstOfs, &lv_SrcRect))
return FALSE;
// w/h of actually read content
lv_W = lv_SrcRect.Right - lv_SrcRect.Left + 1;
lv_H = lv_SrcRect.Bottom - lv_SrcRect.Top + 1;
// remember previous position
lv_PrvLen = lv_Len;
// loop through rows of buffer
for (lv_Y = 0; lv_Y < lv_H; ++lv_Y)
{
// reset output position of current row
lv_N = 0;
// loop through columns
for (lv_X = 0; lv_X < lv_W; ++lv_X)
{
// is output full?
if (lv_Len + lv_N > in_MaxLen)
break;
// get character from screen buffer, ignore attributes
lv_C = lv_BufData[lv_Y * lv_DstSze.X + lv_X].Char.UnicodeChar;
// append character
out_Str[lv_Len + lv_N++] = lv_C;
}
// remove spaces at the end of the line
while (lv_N > 0 && out_Str[lv_Len+lv_N-1] == ' ')
--lv_N;
// if row was not blank
if (lv_N > 0)
{
// update output position
lv_Len += lv_N;
// is output not full?
if (lv_Len + 2 < in_MaxLen)
{
// append cr/lf
out_Str[lv_Len++] = '\r';
out_Str[lv_Len++] = '\n';
}
}
}
// update screen position
lv_SrcRect.Top = (INT16)(lv_SrcRect.Top + lv_H);
lv_SrcRect.Bottom = (INT16)(lv_SrcRect.Bottom + lv_H);
// until nothing is added or no more screen rows
} while (lv_PrvLen != lv_Len && lv_SrcRect.Bottom < lv_Info.dwSize.Y);
// remove last cr/lf
if (lv_Len > 2)
lv_Len -= 2;
// append eos
out_Str[lv_Len] = 0;
// total screen buffer size in characters
lv_Size = lv_Info.dwSize.X * lv_Info.dwSize.Y;
// clear the buffer with spaces
FillConsoleOutputCharacter(in_RcInfo->hCon, ' ', lv_Size, lv_DstOfs, &lv_Written);
// reset cursor position to (0,0)
SetConsoleCursorPosition(in_RcInfo->hCon, lv_DstOfs);
// done
return TRUE;
}
/**********************************/
/* clear buffer of hidden console */
/**********************************/
BOOL Shell_ClearRedirectConsole(TRedConInfo *in_RcInfo)
{
/* locals */
INT lv_Size;
COORD lv_ClrOfs;
DWORD lv_Written;
CONSOLE_SCREEN_BUFFER_INFO lv_Info;
// validate
if (!in_RcInfo->hCon)
return FALSE;
// get current buffer info
if (!GetConsoleScreenBufferInfo(in_RcInfo->hCon, &lv_Info))
return FALSE;
// clear from (0,0) onward
lv_ClrOfs.X = 0;
lv_ClrOfs.Y = 0;
// total screen buffer size in characters
lv_Size = lv_Info.dwSize.X * lv_Info.dwSize.Y;
// clear the buffer with spaces
FillConsoleOutputCharacter(in_RcInfo->hCon, ' ', lv_Size, lv_ClrOfs, &lv_Written);
// reset cursor position to (0,0)
SetConsoleCursorPosition(in_RcInfo->hCon, lv_ClrOfs);
// done
return TRUE;
}
编辑 2021 年：
Windows 10 现在有 ConPTY API（又名伪控制台），它基本上允许任何程序充当另一个程序的控制台，从而可以捕获直接写入的输出控制台。
这使我的原始答案对于支持 ConPTY 的 Windows 版本已过时。
原回答：
来自reference：
WriteConsole fails if it is used with a standard handle that is redirected to a file. If an application processes multilingual output that can be redirected, determine whether the output handle is a console handle (one method is to call the GetConsoleMode function and check whether it succeeds). If the handle is a console handle, call WriteConsole. If the handle is not a console handle, the output is redirected and you should call WriteFile to perform the I/O.
这仅适用于您控制要重定向的应用程序的源代码的情况。我最近不得不 重定向来自一个无条件调用 WriteConsole() 的闭源应用程序 的输出，因此它无法正常重定向。
读取控制台屏幕缓冲区（如 WriteConsole() API 并在必要时调用 WriteFile()。否则调用原始进程WriteConsole() 函数。
我根据Using Detours的例子创建了一个hook DLL:
#include <windows.h>
#include <detours.h>
// Target pointer for the uninstrumented WriteConsoleW API.
//
auto WriteConsoleW_orig = &WriteConsoleW;
// Detour function that replaces the WriteConsoleW API.
//
BOOL WINAPI WriteConsoleW_hooked(
_In_ HANDLE hConsoleOutput,
_In_ const VOID *lpBuffer,
_In_ DWORD nNumberOfCharsToWrite,
_Out_ LPDWORD lpNumberOfCharsWritten,
_Reserved_ LPVOID lpReserved
)
{
// Check if this actually is a console screen buffer handle.
DWORD mode;
if( GetConsoleMode( hConsoleOutput, &mode ) )
{
// Forward to the original WriteConsoleW() function.
return WriteConsoleW_orig( hConsoleOutput, lpBuffer, nNumberOfCharsToWrite, lpNumberOfCharsWritten, lpReserved );
}
else
{
// This is a redirected handle (e. g. a file or a pipe). We multiply with sizeof(WCHAR), because WriteFile()
// expects the number of bytes, but WriteConsoleW() gets passed the number of characters.
BOOL result = WriteFile( hConsoleOutput, lpBuffer, nNumberOfCharsToWrite * sizeof(WCHAR), lpNumberOfCharsWritten, nullptr );
// WriteFile() returns number of bytes written, but WriteConsoleW() has to return the number of characters written.
if( lpNumberOfCharsWritten )
*lpNumberOfCharsWritten /= sizeof(WCHAR);
return result;
}
}
// DllMain function attaches and detaches the WriteConsoleW_hooked detour to the
// WriteConsoleW target function. The WriteConsoleW target function is referred to
// through the WriteConsoleW_orig target pointer.
//
BOOL WINAPI DllMain(HINSTANCE hinst, DWORD dwReason, LPVOID reserved)
{
if (DetourIsHelperProcess()) {
return TRUE;
}
if (dwReason == DLL_PROCESS_ATTACH) {
DetourRestoreAfterWith();
DetourTransactionBegin();
DetourUpdateThread(GetCurrentThread());
DetourAttach(&(PVOID&)WriteConsoleW_orig, WriteConsoleW_hooked);
DetourTransactionCommit();
}
else if (dwReason == DLL_PROCESS_DETACH) {
DetourTransactionBegin();
DetourUpdateThread(GetCurrentThread());
DetourDetach(&(PVOID&)WriteConsoleW_orig, WriteConsoleW_hooked);
DetourTransactionCommit();
}
return TRUE;
}
注意：在WriteFile()分支我不写BOM（字节顺序标记），因为它并不总是需要的（例如当重定向到管道而不是文件或附加到现有文件时）。使用 DLL 将进程输出重定向到文件的应用程序可以在启动重定向进程之前自行编写 UTF-16 LE BOM。
目标进程是使用 DetourCreateProcessWithDllExW(), specifying the name of our hook DLL as argument for the lpDllName parameter. The other arguments are identical to how you create a redirected process via the CreateProcessW() API 创建的。我就不细说了，因为这些都有据可查。