Golang系统调用错误如何判断

<span style="color:#00f">file</span>, <span style="color:#00f">err</span> := os.Open("config.yaml")
<span style="color:#a50">if</span> err != <span style="color:#a50;font-weight:bold">nil</span> {
    log.Fatal("打开文件失败:", err)
}
<span style="color:#a50;font-weight:bold">defer</span> file.Close()

<span style="color:#00f">_,</span> <span style="color:#00f">err</span> := os.Stat("/path/to/nonexistent")
<span style="color:#a50">if</span> errors.Is(err, os.ErrNotExist) {
    log.Println("文件不存在")
} <span style="color:#a50">else</span> <span style="color:#a50">if</span> err != <span style="color:#a50;font-weight:bold">nil</span> {
    log.Println("其他错误:", err)
}

<span style="color:#00f">_,</span> <span style="color:#00f">err</span> := syscall.Getpagesize()
<span style="color:#a50">if</span> errno, ok := err.(syscall.Errno); ok {
    <span style="color:#a50">switch</span> errno {
    <span style="color:#a50">case</span> 0:
        log.Println("调用成功")
    <span style="color:#a50">default</span>:
        log.Println("系统错误码:", errno)
    }
}