It should be noted that this function performs access checks based on the real UID and real GID of the process running PHP. These aren't necessarily the same as the effective UID and GID.
In other words, it may well be that access() returns “true” for a particular permission, but an fopen() operation which requires the same permission will fail, and vice versa.
Keep that in mind if you use access() for such checks.
posix_access
(PHP 5 >= 5.1.0, PHP 7, PHP 8)
posix_access — Determine accessibility of a file
说明
posix_access() checks the user's permission of a file.
参数
-
filename -
The name of the file to be tested.
-
flags -
A mask consisting of one or more of
POSIX_F_OK,POSIX_R_OK,POSIX_W_OKandPOSIX_X_OK.POSIX_R_OK,POSIX_W_OKandPOSIX_X_OKrequest checking whether the file exists and has read, write and execute permissions, respectively.POSIX_F_OKjust requests checking for the existence of the file.
返回值
成功时返回 true， 或者在失败时返回 false。
示例
示例 #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);
}
?>注释
参见
- posix_get_last_error() - Retrieve the error number set by the last posix function that failed
- posix_strerror() - Retrieve the system error message associated with the given errno
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User Contributed Notes 1 note
unixguy at earth dot com ¶
10 years ago
