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# posix_access

(PHP 5 >= 5.1.0RC1)

posix_access -- Determine accessibility of a file

## 说明

bool posix_access ( string file [, int mode] )

posix_access() checks the user's permission of a file.

> 注: 当安全模式被激活时，PHP 将检查被操作的文件或者目录是否与正在执行的脚本有相同的 UID（所有者）。

## 参数

file

  The name of the file to be tested.

mode

  A mask consisting of one or more of `POSIX_F_OK`, `POSIX_R_OK`, `POSIX_W_OK` and `POSIX_X_OK`. Defaults to `POSIX_F_OK`.

  `POSIX_R_OK`, `POSIX_W_OK` and `POSIX_X_OK` request checking whether the file exists and has read, write and execute permissions, respectively. `POSIX_F_OK` just requests checking for the existence of the file.

## 返回值

如果成功则返回 `TRUE`，失败则返回 `FALSE`。

## 范例

例子 1. posix_access() example

This example will check if the $file is readable and writable, otherwise will print an error message.

`<?php $file = 'some_file'; if (posix_access($file, POSIX_R_OK | POSIX_W_OK)) { echo 'The file is readable and writable!'; } else { $error = posix_get_last_error(); echo "Error $error: " . posix_strerror($error); } ?>`

## 参见

posix_get_last_error()
posix_strerror()

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POSIX Functions | 上一级 | posix_ctermid