Linux 改变文件大小的方法

电连天下 發表於 2023-7-11 00:00:00

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函数原型：</p>
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<code class="bash comments">#include <unistd.h></code>
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<code class="bash plain">int ftruncate(int fd, off_t length);        </code><code class="bash plain">//</code><code class="bash plain">改变文件大小为length指定大小;返回值执行成功则返回0，失败返回-1。</code>
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函数ftruncate会将参数fd指定的文件大小改为参数length指定的大小。参数fd为已打开的文件描述词，而且必须是以写入模式打开的文件。如果原来的文件大小比参数length大，则超过的部分会被删去。     </p>
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test.c</p>
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<code class="bash comments">#include<sys/types.h></code>
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<code class="bash comments">#include<sys/stat.h></code>
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<code class="bash comments">#include<fcntl.h></code>
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<code class="bash comments">#include<unistd.h></code>
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<code class="bash comments">#include<strings.h></code>
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<code class="bash comments">#include<stdio.h></code>
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<code class="bash plain">int main(int argc,char** argv)</code>
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<code class="bash plain">{</code>
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<code class="bash spaces">    </code><code class="bash plain">struct stat st;</code>
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<code class="bash spaces">    </code><code class="bash plain">bzero(&st,sizeof(st));</code>
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<code class="bash spaces">    </code><code class="bash plain">stat(argv,&st);</code>
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<code class="bash spaces">    </code><code class="bash functions">printf</code><code class="bash plain">(</code><code class="bash string">"%s %ld\n"</code><code class="bash plain">,argv,st.st_size);</code>
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<code class="bash spaces">    </code><code class="bash plain">int fd=</code><code class="bash functions">open</code><code class="bash plain">(argv,O_RDWR);</code>
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<code class="bash spaces">    </code><code class="bash plain">ftruncate(fd,20);</code>
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<code class="bash spaces">    </code><code class="bash plain">bzero(&st,sizeof(st));</code>
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<code class="bash spaces">    </code><code class="bash plain">stat(argv,&st);</code>
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<code class="bash spaces">    </code><code class="bash functions">printf</code><code class="bash plain">(</code><code class="bash string">"%s %ld\n"</code><code class="bash plain">,argv,st.st_size);</code>
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<code class="bash spaces">    </code><code class="bash plain">close(fd);</code>
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<code class="bash spaces">    </code><code class="bash keyword">return</code> <code class="bash plain">0;</code>
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<code class="bash plain">}</code>
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<span><img title="Linux 改变文件大小的方法" alt="Linux 改变文件大小的方法" src="https://zhuji.jb51.net/uploads/img/202305/c90a37e8f49fbae64c5f713ec9f94381.jpg"></span></p>
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<span><strong>总结</strong></span></p>
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以上所述是小编给大家介绍的Linux 改变文件大小的方法，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对网站的支持！</p>
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原文链接：https://www.cnblogs.com/meihao1203/p/8440922.html</p>

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Linux 改变文件大小的方法