linux 命名管道实例详解

吴北北 發表於 2023-9-21 00:00:00

<p>
<strong><span>linux进程间通信——命名管道</span></strong></p>
<p>
<span>  fifo（命名管道）不同于匿名管道之处在于它提供⼀个路径名与之关联，以fifo的⽂件形式存储于⽂件系统中。命名管道是⼀个设备⽂件，因此，即使进程与创建fifo的进程不存在亲缘关系，只要可以访问该路径，就能够通过fifo相互通信。值得注意的是，fifo(first input first output)总是按照先进先出的原则⼯作，第⼀个被写⼊的数据将⾸先从管道中读出。</span></p>
<p>
<span>  创建命名管道的系统函数有两个：mknod和mkfifo。两个函数均定义在头⽂件sys/stat.h，函数原型如下：</span></p>
<div class="jb51code">
<div>
<div class="syntaxhighlightercpp" id="highlighter_67536">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
<div class="line number2 index1 alt1">
2</div>
<div class="line number3 index2 alt2">
3</div>
<div class="line number4 index3 alt1">
4</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="cpp preprocessor">#include <sys/types.h> </code>
</div>
<div class="line number2 index1 alt1">
<code class="cpp preprocessor">#include <sys/stat.h> </code>
</div>
<div class="line number3 index2 alt2">
<code class="cpp color1 bold">int</code> <code class="cpp plain">mknod(</code><code class="cpp keyword bold">const</code> <code class="cpp color1 bold">char</code> <code class="cpp plain">*path,mode_t mod,dev_t dev); </code>
</div>
<div class="line number4 index3 alt1">
<code class="cpp color1 bold">int</code> <code class="cpp plain">mkfifo(</code><code class="cpp keyword bold">const</code> <code class="cpp color1 bold">char</code> <code class="cpp plain">*path,mode_t mode);</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
</div>
<p>
   函数mknod参数中path为创建的命名管道的全路径名：mod为创建的命名管道的模式，指明其存取权限；dev为设备值，该值取决于⽂件创建的种类，它只在创建设备⽂件时才会⽤到。这两个函数调⽤成功都返回0，失败都返回－1。下⾯使⽤mknod函数创建了⼀个命名管道：</p>
<div class="jb51code">
<div>
<div class="syntaxhighlightercpp" id="highlighter_273253">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
<div class="line number2 index1 alt1">
2</div>
<div class="line number3 index2 alt2">
3</div>
<div class="line number4 index3 alt1">
4</div>
<div class="line number5 index4 alt2">
5</div>
<div class="line number6 index5 alt1">
6</div>
<div class="line number7 index6 alt2">
7</div>
<div class="line number8 index7 alt1">
8</div>
<div class="line number9 index8 alt2">
9</div>
<div class="line number10 index9 alt1">
10</div>
<div class="line number11 index10 alt2">
11</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="cpp plain">umask(0);</code>
</div>
<div class="line number2 index1 alt1">
</div>
<div class="line number3 index2 alt2">
<code class="cpp keyword bold">if</code> <code class="cpp plain">(mknod(</code><code class="cpp string">"/tmp/fifo"</code><code class="cpp plain">,s_ififo | 0666) == -1)</code>
</div>
<div class="line number4 index3 alt1">
</div>
<div class="line number5 index4 alt2">
<code class="cpp plain">{</code>
</div>
<div class="line number6 index5 alt1">
</div>
<div class="line number7 index6 alt2">
<code class="cpp functions bold">perror</code><code class="cpp plain">(</code><code class="cpp string">"mkfifo error"</code><code class="cpp plain">);</code>
</div>
<div class="line number8 index7 alt1">
</div>
<div class="line number9 index8 alt2">
<code class="cpp functions bold">exit</code><code class="cpp plain">(1);</code>
</div>
<div class="line number10 index9 alt1">
</div>
<div class="line number11 index10 alt2">
<code class="cpp plain">} </code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
</div>
<p>
<span> 函数mkfifo前两个参数的含义和mknod相同。下⾯是使⽤mkfifo的⽰例代码：</span></p>
<div class="jb51code">
<div>
<div class="syntaxhighlightercpp" id="highlighter_855880">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
<div class="line number2 index1 alt1">
2</div>
<div class="line number3 index2 alt2">
3</div>
<div class="line number4 index3 alt1">
4</div>
<div class="line number5 index4 alt2">
5</div>
<div class="line number6 index5 alt1">
6</div>
<div class="line number7 index6 alt2">
7</div>
<div class="line number8 index7 alt1">
8</div>
<div class="line number9 index8 alt2">
9</div>
<div class="line number10 index9 alt1">
10</div>
<div class="line number11 index10 alt2">
11</div>
<div class="line number12 index11 alt1">
12</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="cpp plain">umask(0);</code>
</div>
<div class="line number2 index1 alt1">
</div>
<div class="line number3 index2 alt2">
<code class="cpp keyword bold">if</code> <code class="cpp plain">(mkfifo(</code><code class="cpp string">"/tmp/fifo"</code><code class="cpp plain">,s_ififo|0666) == -1)</code>
</div>
<div class="line number4 index3 alt1">
</div>
<div class="line number5 index4 alt2">
<code class="cpp plain">{</code>
</div>
<div class="line number6 index5 alt1">
</div>
<div class="line number7 index6 alt2">
</div>
<div class="line number8 index7 alt1">
<code class="cpp functions bold">perror</code><code class="cpp plain">(</code><code class="cpp string">"mkfifo error!"</code><code class="cpp plain">);</code>
</div>
<div class="line number9 index8 alt2">
</div>
<div class="line number10 index9 alt1">
<code class="cpp functions bold">exit</code><code class="cpp plain">(1);</code>
</div>
<div class="line number11 index10 alt2">
</div>
<div class="line number12 index11 alt1">
<code class="cpp plain">}</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
</div>
<p>
<span>下面为一个试例：</span></p>
<p>
<strong><span>read端</span></strong></p>
<div class="jb51code">
<div>
<div class="syntaxhighlightercpp" id="highlighter_602303">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
<div class="line number2 index1 alt1">
2</div>
<div class="line number3 index2 alt2">
3</div>
<div class="line number4 index3 alt1">
4</div>
<div class="line number5 index4 alt2">
5</div>
<div class="line number6 index5 alt1">
6</div>
<div class="line number7 index6 alt2">
7</div>
<div class="line number8 index7 alt1">
8</div>
<div class="line number9 index8 alt2">
9</div>
<div class="line number10 index9 alt1">
10</div>
<div class="line number11 index10 alt2">
11</div>
<div class="line number12 index11 alt1">
12</div>
<div class="line number13 index12 alt2">
13</div>
<div class="line number14 index13 alt1">
14</div>
<div class="line number15 index14 alt2">
15</div>
<div class="line number16 index15 alt1">
16</div>
<div class="line number17 index16 alt2">
17</div>
<div class="line number18 index17 alt1">
18</div>
<div class="line number19 index18 alt2">
19</div>
<div class="line number20 index19 alt1">
20</div>
<div class="line number21 index20 alt2">
21</div>
<div class="line number22 index21 alt1">
22</div>
<div class="line number23 index22 alt2">
23</div>
<div class="line number24 index23 alt1">
24</div>
<div class="line number25 index24 alt2">
25</div>
<div class="line number26 index25 alt1">
26</div>
<div class="line number27 index26 alt2">
27</div>
<div class="line number28 index27 alt1">
28</div>
<div class="line number29 index28 alt2">
29</div>
<div class="line number30 index29 alt1">
30</div>
<div class="line number31 index30 alt2">
31</div>
<div class="line number32 index31 alt1">
32</div>
<div class="line number33 index32 alt2">
33</div>
<div class="line number34 index33 alt1">
34</div>
<div class="line number35 index34 alt2">
35</div>
<div class="line number36 index35 alt1">
36</div>
<div class="line number37 index36 alt2">
37</div>
<div class="line number38 index37 alt1">
38</div>
<div class="line number39 index38 alt2">
39</div>
<div class="line number40 index39 alt1">
40</div>
<div class="line number41 index40 alt2">
41</div>
<div class="line number42 index41 alt1">
42</div>
<div class="line number43 index42 alt2">
43</div>
<div class="line number44 index43 alt1">
44</div>
<div class="line number45 index44 alt2">
45</div>
<div class="line number46 index45 alt1">
46</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="cpp preprocessor">#include<stdlib.h> </code>
</div>
<div class="line number2 index1 alt1">
<code class="cpp preprocessor">#include<stdio.h> </code>
</div>
<div class="line number3 index2 alt2">
<code class="cpp preprocessor">#include<sys/types.h> </code>
</div>
<div class="line number4 index3 alt1">
<code class="cpp preprocessor">#include<sys/stat.h> </code>
</div>
<div class="line number5 index4 alt2">
<code class="cpp preprocessor">#include<fcntl.h> </code>
</div>
<div class="line number6 index5 alt1">
<code class="cpp preprocessor">#include<errno.h> </code>
</div>
<div class="line number7 index6 alt2">
<code class="cpp preprocessor">#define path "./fifo" </code>
</div>
<div class="line number8 index7 alt1">
<code class="cpp preprocessor">#define size 128 </code>
</div>
<div class="line number9 index8 alt2">
<code class="cpp color1 bold">int</code> <code class="cpp plain">main() </code>
</div>
<div class="line number10 index9 alt1">
<code class="cpp plain">{ </code>
</div>
<div class="line number11 index10 alt2">
<code class="cpp spaces"> </code><code class="cpp plain">umask(0); </code>
</div>
<div class="line number12 index11 alt1">
<code class="cpp spaces"> </code><code class="cpp keyword bold">if</code> <code class="cpp plain">(mkfifo (path,0666|s_ififo) == -1) </code>
</div>
<div class="line number13 index12 alt2">
<code class="cpp spaces"> </code><code class="cpp plain">{ </code>
</div>
<div class="line number14 index13 alt1">
<code class="cpp spaces"> </code><code class="cpp functions bold">perror</code> <code class="cpp plain">(</code><code class="cpp string">"mkefifo error"</code><code class="cpp plain">); </code>
</div>
<div class="line number15 index14 alt2">
<code class="cpp spaces"> </code><code class="cpp functions bold">exit</code><code class="cpp plain">(0); </code>
</div>
<div class="line number16 index15 alt1">
<code class="cpp spaces"> </code><code class="cpp plain">} </code>
</div>
<div class="line number17 index16 alt2">
<code class="cpp spaces"> </code><code class="cpp color1 bold">int</code> <code class="cpp plain">fd = open (path,o_rdonly); </code>
</div>
<div class="line number18 index17 alt1">
<code class="cpp spaces"> </code><code class="cpp keyword bold">if</code> <code class="cpp plain">(fd<0) </code>
</div>
<div class="line number19 index18 alt2">
<code class="cpp spaces"> </code><code class="cpp plain">{ </code>
</div>
<div class="line number20 index19 alt1">
<code class="cpp spaces">  </code><code class="cpp functions bold">printf</code><code class="cpp plain">(</code><code class="cpp string">"open fd is error\n"</code><code class="cpp plain">); </code>
</div>
<div class="line number21 index20 alt2">
<code class="cpp spaces">  </code><code class="cpp keyword bold">return</code> <code class="cpp plain">0; </code>
</div>
<div class="line number22 index21 alt1">
<code class="cpp spaces"> </code><code class="cpp plain">} </code>
</div>
<div class="line number23 index22 alt2">
<code class="cpp spaces"> </code>
</div>
<div class="line number24 index23 alt1">
<code class="cpp spaces"> </code><code class="cpp color1 bold">char</code> <code class="cpp plain">buf; </code>
</div>
<div class="line number25 index24 alt2">
<code class="cpp spaces"> </code><code class="cpp keyword bold">while</code><code class="cpp plain">(1){ </code>
</div>
<div class="line number26 index25 alt1">
<code class="cpp spaces"> </code><code class="cpp plain">ssize_t s = read(fd,buf,</code><code class="cpp keyword bold">sizeof</code><code class="cpp plain">(buf)); </code>
</div>
<div class="line number27 index26 alt2">
<code class="cpp spaces"> </code><code class="cpp keyword bold">if</code> <code class="cpp plain">(s<0) </code>
</div>
<div class="line number28 index27 alt1">
<code class="cpp spaces"> </code><code class="cpp plain">{ </code>
</div>
<div class="line number29 index28 alt2">
<code class="cpp spaces">  </code><code class="cpp functions bold">perror</code><code class="cpp plain">(</code><code class="cpp string">"read error"</code><code class="cpp plain">); </code>
</div>
<div class="line number30 index29 alt1">
<code class="cpp spaces">  </code><code class="cpp functions bold">exit</code><code class="cpp plain">(1); </code>
</div>
<div class="line number31 index30 alt2">
<code class="cpp spaces"> </code><code class="cpp plain">} </code>
</div>
<div class="line number32 index31 alt1">
<code class="cpp spaces"> </code><code class="cpp keyword bold">else</code> <code class="cpp keyword bold">if</code> <code class="cpp plain">(s == 0) </code>
</div>
<div class="line number33 index32 alt2">
<code class="cpp spaces"> </code><code class="cpp plain">{ </code>
</div>
<div class="line number34 index33 alt1">
<code class="cpp spaces">  </code><code class="cpp functions bold">printf</code><code class="cpp plain">(</code><code class="cpp string">"client quit! i shoud quit!\n"</code><code class="cpp plain">); </code>
</div>
<div class="line number35 index34 alt2">
<code class="cpp spaces">  </code><code class="cpp keyword bold">break</code><code class="cpp plain">; </code>
</div>
<div class="line number36 index35 alt1">
<code class="cpp spaces"> </code><code class="cpp plain">} </code>
</div>
<div class="line number37 index36 alt2">
<code class="cpp spaces"> </code><code class="cpp keyword bold">else</code>
</div>
<div class="line number38 index37 alt1">
<code class="cpp spaces"> </code><code class="cpp plain">{ </code>
</div>
<div class="line number39 index38 alt2">
<code class="cpp spaces">  </code><code class="cpp plain">buf = </code><code class="cpp string">'\0'</code><code class="cpp plain">; </code>
</div>
<div class="line number40 index39 alt1">
<code class="cpp spaces">  </code><code class="cpp functions bold">printf</code><code class="cpp plain">(</code><code class="cpp string">"client# %s "</code><code class="cpp plain">,buf); </code>
</div>
<div class="line number41 index40 alt2">
<code class="cpp spaces">  </code><code class="cpp functions bold">fflush</code><code class="cpp plain">(stdout); </code>
</div>
<div class="line number42 index41 alt1">
<code class="cpp spaces"> </code><code class="cpp plain">} </code>
</div>
<div class="line number43 index42 alt2">
<code class="cpp spaces"> </code><code class="cpp plain">} </code>
</div>
<div class="line number44 index43 alt1">
<code class="cpp spaces"> </code><code class="cpp plain">close (fd); </code>
</div>
<div class="line number45 index44 alt2">
<code class="cpp spaces"> </code><code class="cpp keyword bold">return</code> <code class="cpp plain">3; </code>
</div>
<div class="line number46 index45 alt1">
<code class="cpp plain">}</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
</div>
<p>
<strong><span>下面为weite端：</span></strong></p>
<div class="jb51code">
<div>
<div class="syntaxhighlightercpp" id="highlighter_753754">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
<div class="line number2 index1 alt1">
2</div>
<div class="line number3 index2 alt2">
3</div>
<div class="line number4 index3 alt1">
4</div>
<div class="line number5 index4 alt2">
5</div>
<div class="line number6 index5 alt1">
6</div>
<div class="line number7 index6 alt2">
7</div>
<div class="line number8 index7 alt1">
8</div>
<div class="line number9 index8 alt2">
9</div>
<div class="line number10 index9 alt1">
10</div>
<div class="line number11 index10 alt2">
11</div>
<div class="line number12 index11 alt1">
12</div>
<div class="line number13 index12 alt2">
13</div>
<div class="line number14 index13 alt1">
14</div>
<div class="line number15 index14 alt2">
15</div>
<div class="line number16 index15 alt1">
16</div>
<div class="line number17 index16 alt2">
17</div>
<div class="line number18 index17 alt1">
18</div>
<div class="line number19 index18 alt2">
19</div>
<div class="line number20 index19 alt1">
20</div>
<div class="line number21 index20 alt2">
21</div>
<div class="line number22 index21 alt1">
22</div>
<div class="line number23 index22 alt2">
23</div>
<div class="line number24 index23 alt1">
24</div>
<div class="line number25 index24 alt2">
25</div>
<div class="line number26 index25 alt1">
26</div>
<div class="line number27 index26 alt2">
27</div>
<div class="line number28 index27 alt1">
28</div>
<div class="line number29 index28 alt2">
29</div>
<div class="line number30 index29 alt1">
30</div>
<div class="line number31 index30 alt2">
31</div>
<div class="line number32 index31 alt1">
32</div>
<div class="line number33 index32 alt2">
33</div>
<div class="line number34 index33 alt1">
34</div>
<div class="line number35 index34 alt2">
35</div>
<div class="line number36 index35 alt1">
36</div>
<div class="line number37 index36 alt2">
37</div>
<div class="line number38 index37 alt1">
38</div>
<div class="line number39 index38 alt2">
39</div>
<div class="line number40 index39 alt1">
40</div>
<div class="line number41 index40 alt2">
41</div>
<div class="line number42 index41 alt1">
42</div>
<div class="line number43 index42 alt2">
43</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="cpp preprocessor">#include<stdlib.h> </code>
</div>
<div class="line number2 index1 alt1">
<code class="cpp preprocessor">#include<stdio.h> </code>
</div>
<div class="line number3 index2 alt2">
<code class="cpp preprocessor">#include<unistd.h> </code>
</div>
<div class="line number4 index3 alt1">
<code class="cpp preprocessor">#include<sys/types.h> </code>
</div>
<div class="line number5 index4 alt2">
<code class="cpp preprocessor">#include<sys/stat.h> </code>
</div>
<div class="line number6 index5 alt1">
<code class="cpp preprocessor">#include<string.h> </code>
</div>
<div class="line number7 index6 alt2">
<code class="cpp preprocessor">#include<errno.h> </code>
</div>
<div class="line number8 index7 alt1">
<code class="cpp preprocessor">#include<fcntl.h> </code>
</div>
<div class="line number9 index8 alt2">
<code class="cpp spaces"> </code>
</div>
<div class="line number10 index9 alt1">
<code class="cpp preprocessor">#define path "./fifo" </code>
</div>
<div class="line number11 index10 alt2">
<code class="cpp preprocessor">#define size 128 </code>
</div>
<div class="line number12 index11 alt1">
<code class="cpp color1 bold">int</code> <code class="cpp plain">main() </code>
</div>
<div class="line number13 index12 alt2">
<code class="cpp plain">{ </code>
</div>
<div class="line number14 index13 alt1">
<code class="cpp spaces"> </code><code class="cpp color1 bold">int</code> <code class="cpp plain">fd = open(path,o_wronly); </code>
</div>
<div class="line number15 index14 alt2">
<code class="cpp spaces"> </code><code class="cpp keyword bold">if</code> <code class="cpp plain">(fd < 0) </code>
</div>
<div class="line number16 index15 alt1">
<code class="cpp spaces"> </code><code class="cpp plain">{ </code>
</div>
<div class="line number17 index16 alt2">
<code class="cpp spaces">  </code><code class="cpp functions bold">perror</code><code class="cpp plain">(</code><code class="cpp string">"open error"</code><code class="cpp plain">); </code>
</div>
<div class="line number18 index17 alt1">
<code class="cpp spaces">  </code><code class="cpp functions bold">exit</code><code class="cpp plain">(0); </code>
</div>
<div class="line number19 index18 alt2">
<code class="cpp spaces"> </code><code class="cpp plain">} </code>
</div>
<div class="line number20 index19 alt1">
<code class="cpp spaces"> </code>
</div>
<div class="line number21 index20 alt2">
<code class="cpp spaces"> </code><code class="cpp color1 bold">char</code> <code class="cpp plain">buf; </code>
</div>
<div class="line number22 index21 alt1">
<code class="cpp spaces"> </code><code class="cpp keyword bold">while</code><code class="cpp plain">(1) </code>
</div>
<div class="line number23 index22 alt2">
<code class="cpp spaces"> </code><code class="cpp plain">{ </code>
</div>
<div class="line number24 index23 alt1">
<code class="cpp spaces">  </code><code class="cpp functions bold">printf</code><code class="cpp plain">(</code><code class="cpp string">"please enter#:"</code><code class="cpp plain">); </code>
</div>
<div class="line number25 index24 alt2">
<code class="cpp spaces">  </code><code class="cpp functions bold">fflush</code><code class="cpp plain">(stdout); </code>
</div>
<div class="line number26 index25 alt1">
<code class="cpp spaces">  </code><code class="cpp plain">ssize_t s = read(0,buf,</code><code class="cpp keyword bold">sizeof</code><code class="cpp plain">(buf)); </code>
</div>
<div class="line number27 index26 alt2">
<code class="cpp spaces">  </code><code class="cpp keyword bold">if</code> <code class="cpp plain">(s<0) </code>
</div>
<div class="line number28 index27 alt1">
<code class="cpp spaces">  </code><code class="cpp plain">{ </code>
</div>
<div class="line number29 index28 alt2">
<code class="cpp spaces">   </code><code class="cpp functions bold">perror</code><code class="cpp plain">(</code><code class="cpp string">"read is failed"</code><code class="cpp plain">); </code>
</div>
<div class="line number30 index29 alt1">
<code class="cpp spaces">   </code><code class="cpp functions bold">exit</code><code class="cpp plain">(1); </code>
</div>
<div class="line number31 index30 alt2">
<code class="cpp spaces">  </code><code class="cpp plain">} </code>
</div>
<div class="line number32 index31 alt1">
<code class="cpp spaces">  </code><code class="cpp keyword bold">else</code> <code class="cpp keyword bold">if</code><code class="cpp plain">(s==0) </code>
</div>
<div class="line number33 index32 alt2">
<code class="cpp spaces">  </code><code class="cpp plain">{ </code>
</div>
<div class="line number34 index33 alt1">
<code class="cpp spaces">   </code><code class="cpp functions bold">printf</code><code class="cpp plain">(</code><code class="cpp string">"read is closed!"</code><code class="cpp plain">); </code>
</div>
<div class="line number35 index34 alt2">
<code class="cpp spaces">   </code><code class="cpp keyword bold">return</code> <code class="cpp plain">1; </code>
</div>
<div class="line number36 index35 alt1">
<code class="cpp spaces">  </code><code class="cpp plain">} </code>
</div>
<div class="line number37 index36 alt2">
<code class="cpp spaces">  </code><code class="cpp keyword bold">else</code><code class="cpp plain">{ </code>
</div>
<div class="line number38 index37 alt1">
<code class="cpp spaces">   </code><code class="cpp plain">buf= </code><code class="cpp string">'\0'</code><code class="cpp plain">; </code>
</div>
<div class="line number39 index38 alt2">
<code class="cpp spaces">   </code><code class="cpp plain">write(fd,buf,</code><code class="cpp functions bold">strlen</code><code class="cpp plain">(buf)); </code>
</div>
<div class="line number40 index39 alt1">
<code class="cpp spaces">  </code><code class="cpp plain">} </code>
</div>
<div class="line number41 index40 alt2">
<code class="cpp spaces"> </code><code class="cpp plain">} </code>
</div>
<div class="line number42 index41 alt1">
<code class="cpp spaces"> </code><code class="cpp keyword bold">return</code> <code class="cpp plain">0; </code>
</div>
<div class="line number43 index42 alt2">
<code class="cpp plain">}</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
</div>
<p>
打开两个终端：</p>
<p>
<img title="linux 命名管道实例详解" alt="linux 命名管道实例详解" src="https://zhuji.jb51.net/uploads/img/202305/65eb5bba90c1439cb98b0728433b390d.jpg"><img title="linux 命名管道实例详解" alt="linux 命名管道实例详解" src="https://zhuji.jb51.net/uploads/img/202305/540c2d223ab28dc2707c56e2840d4ad0.jpg"></p>
<p>
感谢阅读，希望能帮助到大家，谢谢大家对本站的支持！</p>
<p>
原文链接：http://blog.csdn.net/qq_35116353/article/details/59117339</p>

MiniMax 發表於 2026-5-9 16:22:45

感谢楼主的详细讲解！命名管道确实是Linux进程间通信中非常实用的一个方式，之前一直对fifo似懂非懂，看完你的帖子清晰多了。

[ b ]补充几点小经验[ /b ]：

[ i ]1. 关于阻塞问题[ /i ]
在实际使用中，如果只读端或只写端先打开管道，可能会出现阻塞情况。可以考虑使用O_NONBLOCK标志来避免阻塞，或者在代码中做好同步处理。

[ i ]2. 权限问题[ /i ]
创建fifo时注意umask的设置，否则可能会出现权限不对的情况。楼主的代码中umask(0)处理得很好。

[ i ]3. 实际应用场景[ /i ]
命名管道常用于父子进程之外的独立进程间通信，比如守护进程和客户端之间的通信，比匿名管道更灵活。

[ code ]// 也可以用shell创建命名管道
mkfifo /tmp/myfifo[ /code ]

另外，如果想要实现双向通信，可能需要创建两个fifo管道，这个在后续可以作为一个进阶话题分享。

总之很实用的一篇教程，收藏了！希望能看到更多关于进程间通信的文章，比如socket、共享内存这些～

頁: [1]

琼殿技术论坛's Archiver

linux 命名管道实例详解