Mono中的DateTime.ToString返回无效日期（“00/734718/0001 01：41：38”） [英] DateTime.ToString in Mono return invalid date ("00/734718/0001 01:41:38")

问题描述

我正在尝试通过raspbian发行版（Debian GNU / Linux wheezy / sid）将mono（Debian 2.10.8.1-5）正确运行在我的raspberry pi上。我已经安装了单声道与apt-get安装单声道。

但是，我遇到一个有趣的问题，我无法想像。 DateTime.ToString（）方法返回无效的字符串。

下面您可以使用控制台输出找到我的示例程序：

 使用系统; 
 
命名空间MonoTest 
 {
类程序
 {
 static void Main（string [] args）
 {
 DateTime now = DateTime.Now; 
 Console.WriteLine（Year：+ now.Year）; 
 Console.WriteLine（Month：+ now.Month）; 
 Console.WriteLine（Day：+ now.Day）; 
 Console.WriteLine（DayOfWeek：+ now.DayOfWeek）; 
 Console.WriteLine（DateTime.Now：+ DateTime.Now）; 
 Console.WriteLine（DateTime.Now.ToString（yyyy-MM-dd））; 
} 
} 
} 
  

输出：

  pi @ raspberrypi〜/ bin $ mono MonoTest.exe 
年份：2012 
月份：8 
日：3 
 DayOfWeek：Friday 
 DateTime.Now：00/734718/0001 01:41:38 
 0001-00-734718 
   
 
 
有没有人有一个想法这里是什么问题，以及如何说服DateTime.ToString （）返回正确的值？
 
 
 
 更新（8/4/2012）：跟踪问题回到System.Math.Floor。显然，它总是返回0.我将测试程序改为简单：
  static void Main（string [] args）
 {
 Console.WriteLine（Floor（1.5）：+ System.Math.Floor（1.5））; 
} 
  
在Windows上，结果是Floor（1.5）：1而在我的树莓pi上的单声道设置为Floor（1.5）：0。我看到System.Math.Floor被实现为
  [MethodImplAttribute（MethodImplOptions.InternalCall）] 
 public extern静态双层（双d）; 
  
明天，我会进一步研究这个问题。有人知道为什么这个问题可以存在吗？
解决方案
这是Mono bug ＃7938 ，它不仅影响DateTime.ToString，而且直接或间接地将浮点数传递给库调用时，在ARM上运行的Linux发行版为硬浮动ABI构建。有关详细信息，请参阅 C＃on Raspberry Pi 维基页面。目前没有很好的解决方案，缺少运行软浮动发行版。我仍然希望我们可以很快得到固定的单声道运行时间。
 
I am trying to get mono (Debian 2.10.8.1-5) to run properly on my raspberry pi with the raspbian distro ("Debian GNU/Linux wheezy/sid"). I have installed mono with apt-get install mono-complete.

However, I am running into an interesting issue that I cannot figure out. The DateTime.ToString() method returns an invalid string.

Below you can find my sample program with the console output:
using System;

namespace MonoTest
{
    class Program
    {
        static void Main(string[] args)
        {
            DateTime now = DateTime.Now;
            Console.WriteLine("Year: " + now.Year);
            Console.WriteLine("Month: " + now.Month);
            Console.WriteLine("Day: " + now.Day);
            Console.WriteLine("DayOfWeek: " + now.DayOfWeek);
            Console.WriteLine("DateTime.Now: " + DateTime.Now);
            Console.WriteLine(DateTime.Now.ToString("yyyy-MM-dd"));
        }
    }
}
Output:
pi@raspberrypi ~/bin $ mono MonoTest.exe
Year: 2012
Month: 8
Day: 3
DayOfWeek: Friday
DateTime.Now: 00/734718/0001 01:41:38
0001-00-734718
Interestingly enough, 734718 seems to be the the number of days elapsed till today since 01/01/0001. I have tryed it with a fresh installation on a second board but with the same issue.

Does anyone have an idea what the problem here is and how to convince DateTime.ToString() to return the right value?

Update (8/4/2012): After long digging through the mono source code I was able to trace the issue back to System.Math.Floor. Apparently, it always returns 0. I changed my test program to a simple:
static void Main(string[] args)
{
    Console.WriteLine("Floor(1.5): " + System.Math.Floor(1.5));
}
On Windows the result is "Floor(1.5): 1" Whereas on my mono setup on the raspberry pi is "Floor(1.5): 0". I have seen that System.Math.Floor is implemented as
[MethodImplAttribute (MethodImplOptions.InternalCall)]
public extern static double Floor (double d);
Tomorrow, I will look further into this issue. Does anyone know why this issue could exist?
解决方案
This is Mono bug #7938, and it affects not just DateTime.ToString, but ANY function that, directly or indirectly, passes a floating-point number to a library call, when running on ARM with a Linux distro built for the hard-float ABI.  More details are available at the C# on Raspberry Pi wiki page.  There is currently no good fix for this, short of running a soft-float distro.  I'm still hoping we can get a fixed mono runtime soon.

                        
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