C语言 如何在 Visual Studio 2010 上的 Win32 应用程序中查看 printf 输出？

How to view printf output in a Win32 application on Visual Studio 2010?

提问by Nick Van Brunt

How can you view printf output in a Win32application (entering with a WinMain) in Visual Studio 2010?

如何在Visual Studio 2010的Win32应用程序（使用 WinMain 输入）中查看 printf 输出？

回答by rbento

Strictly answering your question, you may use printf-like functions in a Win32 application in Visual Studio 2010 using the winbase.hOutputDebugStringfunction.

严格回答您的问题，您可以使用winbase.hOutputDebugString函数在 Visual Studio 2010 中的 Win32 应用程序中使用类似 printf 的函数。

I wrote a simple program that shows how to do it.

我写了一个简单的程序来展示如何做到这一点。

#include <windows.h>
#include <stdio.h>

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdShow, int nCmdShow)
{
    int number = 10;
    char str[256];
    sprintf_s(str, "It works! - number: %d \n", number);

    OutputDebugString(str);

    return 0;
}

The OutputDebugStringfunction takes an LPCSTRas a parameter. I used the sprintf_sto format the string before printing.

该OutputDebugString函数将 anLPCSTR作为参数。我sprintf_s在打印前使用来格式化字符串。

This would print the result to the Visual Studio 2010 output window.

这会将结果打印到 Visual Studio 2010 输出窗口。

I hope it helps!

我希望它有帮助！

回答by torak

I know that I have done this in the past using the AllocConsolefunction, but I also recall that it was just a little trickier than I expected.

我知道我过去曾使用AllocConsole函数完成此操作，但我也记得它只是比我预期的要复杂一些。

A quick Google search on AllocConsole yields what is apparently a Windows Developer Journal articlethat seems relevant. From there, the following seems similar to what I recall, vague as it is.

在 AllocConsole 上进行快速 Google 搜索，可以找到显然是相关的Windows Developer Journal 文章。从那里开始，以下内容似乎与我所记得的相似，但仍然含糊不清。

void SetStdOutToNewConsole()
{
    int hConHandle;
    long lStdHandle;
    FILE *fp;

    // Allocate a console for this app
    AllocConsole();

    // Redirect unbuffered STDOUT to the console
    lStdHandle = (long)GetStdHandle(STD_OUTPUT_HANDLE);
    hConHandle = _open_osfhandle(lStdHandle, _O_TEXT);
    fp = _fdopen(hConHandle, "w");
    *stdout = *fp;

    setvbuf(stdout, NULL, _IONBF, 0);
}

回答by Hans Passant

You'll need a console window. By far the easiest way to get one is to change a linker option: Project + Properties, Linker, System, SubSystem = Console. Add a main() method:

您将需要一个控制台窗口。到目前为止，最简单的方法是更改​​链接器选项：项目 + 属性、链接器、系统、子系统 = 控制台。添加一个 main() 方法：

int main() {
    return _tWinMain(GetModuleHandle(NULL), NULL, GetCommandLine(), SW_SHOW);
}

回答by Quintin Willison

Thanks torakfor your answer. It helped me a lot.

感谢托拉克的回答。这对我帮助很大。

I needed a bigger scroll back buffer so made a few additions after taking a look at the API functions. Shared here in case it helps anybody else:

我需要一个更大的回滚缓冲区，所以在查看了API 函数后做了一些补充。在这里分享，以防它对其他人有帮助：

void SetStdOutToNewConsole()
{
    // allocate a console for this app
    AllocConsole();

    // redirect unbuffered STDOUT to the console
    HANDLE consoleHandle = GetStdHandle(STD_OUTPUT_HANDLE);
    int fileDescriptor = _open_osfhandle((intptr_t)consoleHandle, _O_TEXT);
    FILE *fp = _fdopen( fileDescriptor, "w" );
    *stdout = *fp;
    setvbuf( stdout, NULL, _IONBF, 0 );

    // give the console window a nicer title
    SetConsoleTitle(L"Debug Output");

    // give the console window a bigger buffer size
    CONSOLE_SCREEN_BUFFER_INFO csbi;
    if ( GetConsoleScreenBufferInfo(consoleHandle, &csbi) )
    {
        COORD bufferSize;
        bufferSize.X = csbi.dwSize.X;
        bufferSize.Y = 9999;
        SetConsoleScreenBufferSize(consoleHandle, bufferSize);
    }
}

This increases the scroll back (screen buffer) height to 9999 lines.

这会将回滚（屏幕缓冲区）高度增加到 9999 行。

Tested on Windows XP and Windows 7.

在 Windows XP 和 Windows 7 上测试。

回答by colin lamarre

Another way which wouldn't require changing existing printf's and also print to VS output window would go something like this:

另一种不需要更改现有 printf 并打印到 VS 输出窗口的方法将是这样的：

#define printf printf2

int __cdecl printf2(const char *format, ...)
{
    char str[1024];

    va_list argptr;
    va_start(argptr, format);
    int ret = vsnprintf(str, sizeof(str), format, argptr);
    va_end(argptr);

    OutputDebugStringA(str);

    return ret;
}

...

printf("remains %s", "the same");

回答by coffeebean

Here is a page that will tell you how to do this, including sample code.

这是一个页面，将告诉您如何执行此操作，包括示例代码。

You must create a console window using AllocConsole(), then associate the C standard file handles to the HANDLEs of the new console window.

您必须使用 AllocConsole() 创建一个控制台窗口，然后将 C 标准文件句柄关联到新控制台窗口的句柄。

回答by User

For MinGW use "_A_SYSTEM" instead "_O_TEXT". So ported Quintin Willisonanswer is as follows:

对于 MinGW，使用“_A_SYSTEM”代替“_O_TEXT”。所以移植Quintin Willison 的答案如下：

#include <io.h>
void SetStdOutToNewConsole()
{
  // allocate a console for this app
  AllocConsole();
  // redirect unbuffered STDOUT to the console
  HANDLE consoleHandle = GetStdHandle(STD_OUTPUT_HANDLE);
  int fileDescriptor = _open_osfhandle((intptr_t)consoleHandle, _A_SYSTEM);
  FILE *fp = _fdopen( fileDescriptor, "w" );
  *stdout = *fp;
  setvbuf( stdout, NULL, _IONBF, 0 );
  // give the console window a nicer title
  SetConsoleTitle(L"Debug Output");
  // give the console window a bigger buffer size
  CONSOLE_SCREEN_BUFFER_INFO csbi;
  if ( GetConsoleScreenBufferInfo(consoleHandle, &csbi) )
  {
    COORD bufferSize;
    bufferSize.X = csbi.dwSize.X;
    bufferSize.Y = 9999;
    SetConsoleScreenBufferSize(consoleHandle, bufferSize);
  }
}