我在原始帖子中的问题已经在其他答案中得到很好的解释。
控制台应用程序使用一个名为的函数isatty()来检测它们的stdout处理程序是连接到管道还是真正的控制台。在管道的情况下，所有输出都以块的形式缓冲和刷新，除非您直接调用fflush(). 在真实控制台的情况下，输出是无缓冲的，并直接打印到控制台输出。
在 Linux 中，您可以使用openpty()创建伪终端并在其中创建您的进程。结果，该进程将认为它在真实终端中运行并使用无缓冲输出。
Windows 似乎没有这样的选项。
经过大量挖掘winapi文档后，我发现这不是真的. 实际上，您可以创建自己的控制台屏幕缓冲区并将其用于stdout您的进程，然后将其无缓冲。
遗憾的是，这不是一个非常舒适的解决方案，因为没有事件处理程序，我们需要轮询新数据。同样，目前我不确定当这个屏幕缓冲区已满时如何处理滚动。
但即使仍然存在一些问题，我认为我已经为那些想要获取无缓冲（和未刷新）Windows 控制台进程输出的人创建了一个非常有用（且有趣）的起点。
#include <windows.h>
#include <stdio.h>
int main(int argc, char* argv[])
{
char cmdline[] = "application.exe"; // process command
HANDLE scrBuff; // our virtual screen buffer
CONSOLE_SCREEN_BUFFER_INFO scrBuffInfo; // state of the screen buffer
// like actual cursor position
COORD scrBuffSize = {80, 25}; // size in chars of our screen buffer
SECURITY_ATTRIBUTES sa; // security attributes
PROCESS_INFORMATION procInfo; // process information
STARTUPINFO startInfo; // process start parameters
DWORD procExitCode; // state of process (still alive)
DWORD NumberOfCharsWritten; // output of fill screen buffer func
COORD pos = {0, 0}; // scr buff pos of data we have consumed
bool quit = false; // flag for reading loop
// 1) Create a screen buffer, set size and clear
sa.nLength = sizeof(sa);
scrBuff = CreateConsoleScreenBuffer( GENERIC_READ | GENERIC_WRITE,
FILE_SHARE_READ | FILE_SHARE_WRITE,
&sa, CONSOLE_TEXTMODE_BUFFER, NULL);
SetConsoleScreenBufferSize(scrBuff, scrBuffSize);
// clear the screen buffer
FillConsoleOutputCharacter(scrBuff, '\0', scrBuffSize.X * scrBuffSize.Y,
pos, &NumberOfCharsWritten);
// 2) Create and start a process
// [using our screen buffer as stdout]
ZeroMemory(&procInfo, sizeof(PROCESS_INFORMATION));
ZeroMemory(&startInfo, sizeof(STARTUPINFO));
startInfo.cb = sizeof(STARTUPINFO);
startInfo.hStdOutput = scrBuff;
startInfo.hStdError = GetStdHandle(STD_ERROR_HANDLE);
startInfo.hStdInput = GetStdHandle(STD_INPUT_HANDLE);
startInfo.dwFlags |= STARTF_USESTDHANDLES;
CreateProcess(NULL, cmdline, NULL, NULL, FALSE,
0, NULL, NULL, &startInfo, &procInfo);
CloseHandle(procInfo.hThread);
// 3) Read from our screen buffer while process is alive
while(!quit)
{
// check if process is still alive or we could quit reading
GetExitCodeProcess(procInfo.hProcess, &procExitCode);
if(procExitCode != STILL_ACTIVE) quit = true;
// get actual state of screen buffer
GetConsoleScreenBufferInfo(scrBuff, &scrBuffInfo);
// check if screen buffer cursor moved since
// last time means new output was written
if (pos.X != scrBuffInfo.dwCursorPosition.X ||
pos.Y != scrBuffInfo.dwCursorPosition.Y)
{
// Get new content of screen buffer
// [ calc len from pos to cursor pos:
// (curY - posY) * lineWidth + (curX - posX) ]
DWORD len = (scrBuffInfo.dwCursorPosition.Y - pos.Y)
* scrBuffInfo.dwSize.X
+(scrBuffInfo.dwCursorPosition.X - pos.X);
char buffer[len];
ReadConsoleOutputCharacter(scrBuff, buffer, len, pos, &len);
// Print new content
// [ there is no newline, unused space is filled with '\0'
// so we read char by char and if it is '\0' we do
// new line and forward to next real char ]
for(int i = 0; i < len; i++)
{
if(buffer[i] != '\0') printf("%c",buffer[i]);
else
{
printf("\n");
while((i + 1) < len && buffer[i + 1] == '\0')i++;
}
}
// Save new position of already consumed data
pos = scrBuffInfo.dwCursorPosition;
}
// no new output so sleep a bit before next check
else Sleep(100);
}
// 4) Cleanup and end
CloseHandle(scrBuff);
CloseHandle(procInfo.hProcess);
return 0;
}