如何在Windows上以编程方式执行ping测试？ [英] How to perform a ping-test programmatically on Windows?

问题描述

我想在 Windows 上的C命令行程序中进行IP测试。

I'd like to make an IP-test in a C command line program on Windows .

现在我在以下位置使用cmd命令我的程序是这样的：

Now I'm using the cmd-command in my program with something like this:

if(system("ping -c1 8.8.8.8  -w 2 ") == 0){
    printf("request successful\n");
    return true; 
}else{
    printf("request not successful\n");
    return false;
}

请注意，上面的代码只是一个示例：在我的程序中，我将尝试ping设备，看它们是否在线；如果不是，我知道存在连接问题。因为我只需要连接状态，所以不需要显示结果。

Please note that the code above is just an example: with my program I will try to ping some devices, to see if they are online; if not I know there is a connection issue. Since I need only the connection status there is no need to show up the results.

是否有另一种方法可以通过编程方式进行同样的操作，因此无需使用cmd-window ？就像在后台隐藏请求一样。

Is there another way to do the same programmatically, so without cmd-window? Just like a hidden request in the background.

推荐答案

如果在 Windows 上，您需要以编程方式检查是否主机可以访问，我建议使用 _popen（） 而不是 system（）。

If on Windows you need to check programmatically if an host is reachable, I suggest using _popen() instead of system().

实际上，使用 管道 ，您可以使用 system（），但除​​此之外，其输出还会重定向到流。之后，您可以完全访问流，就像处理文件一样，读取输出并解析所需的内容。

In fact with pipes you can execute a command like with system(), but in addition its output is redirected to a stream. After that you can access the stream exactly how you'd do with a file, reading the output and parsing whatever you need.

在此链接，您可以找到<$ c的Microsoft官方文档$ c> _popen（）。您将能够轻松找到所有相关功能（例如 _pclose（））。

At this link you can find Microsoft official documentation for _popen(). You will be easily able to find all related functions (such as _pclose()).

在以下示例程序中，<$发送c $ c> ping 命令（仅向Google DNS服务器请求两次回显以节省时间）。然后，以文本读取模式打开的获取的 FILE * 用于通过 normal 循环的 fread访问流。 （）调用：

In the following demonstrative program a ping command is sent (asking for only two echoes to Google DNS server in order to save time). Then the obtained FILE *, opened in textual read mode, is used to access the stream with a normal loop of fread() calls:

#include<stdio.h>
#include<stdlib.h>
#include<string.h>

#define BUFFER_SIZE 1024

char buffer[BUFFER_SIZE] = { 0 };

int main( void )
{
    FILE * pipe = _popen( "ping 8.8.8.8 -n 2", "rt" );
    if( pipe != NULL )
    {
        int rd = 0, ret;
    
        while( ( ret = fread( buffer+rd, 1, BUFFER_SIZE - rd, pipe ) ) > 0 )
        {
            rd += ret;
        }
    
        if( strstr( buffer, "TTL=" ) != NULL )
        {
            printf( "\nThe host is reachable!\n" );
        }
        else
        {
            printf( "\nThe host is NOT reachable!\n" );
        }
    
        //printf( "%d bytes read\n\n%s\n", rd, buffer );

        _pclose( pipe );
    }
    else
    {
        printf( "Error in pipe opening!\n" );  
    }
    return 0;
}

一些进一步的解释

• 在此示例中，仅验证简单主机 reachability 。如果至少有回声返回，则认为主机是可访问的。这是您可能需要解析的任何其他信息的起点。


• 我已经通过检查 TTL = 子字符串，如果可以成功ping操作，我肯定会以每种语言显示（根据PC设置，输出可能以不同的语言打印）。


• 将缓冲区大小调整为查找所需的子字符串所需的长度。在我的示例中，1024字节足以满足预期的响应长度。


• 您可以找到并注释整个缓冲区的打印内容。您可以使用该字符串检查所需的所有内容（例如平均ping时间）。


• 要从信息流中读取内容，请随时使用自己喜欢的内容功能。另一个流行的替代方法是 fgets（），这一次可以很好地读取和解析一行，并且还需要较小的读取缓冲区。



Some further explanation

• In this example only simple host reachability is verified. An host is considered reachable if at least an echo comes back. It is a starting point for any other information you might need to parse.
• I've done it by checking the presence of TTL= substring, that I'm sure will be present in every language in case of successful ping (the output may be printed in different languages according to PC settings).
• Tailor your buffer size to the length you expect is required to find the needed substring. In my example 1024 bytes were far enough for the expected response length.
• You can find, commented, the print of the whole buffer. You can use that string to check everything you need (for example average ping time).
• In order to read from the stream, feel free to use your favourite function. Another popular alternative would be fgets(), that would be great to read and parse one line at a time, and would also require a smaller reading buffer.

尽管问题是关于Windows的，但我不得不说基于 popen（）， pclose（）等，在Linux上将非常相似。

Though the question is about Windows, I have to say that the implementation on Linux would be very similar, based on popen(), pclose() and so on.

您可以在手册页。

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