(PHP 5 >= 5.1.0, PHP 7, PHP 8)
posix_access — Determine accessibility of a file
$filename, int $flags = 0): boolposix_access() checks the user's permission of a file.
filenameThe name of the file to be tested.
flags
A mask consisting of one or more of POSIX_F_OK,
POSIX_R_OK, POSIX_W_OK and
POSIX_X_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.
成功时返回 true， 或者在失败时返回 false。
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);
}
?>