posix_access
(PHP 5 >= 5.1.0)
posix_access — Determine accessibility of a file
Description
posix_access() checks the user's permission of a file.
Parameters
- 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. 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. 
Return Values
Returns TRUE on success or FALSE on failure.
Examples
Example #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);
}
?>
Notes
Note: When safe mode is enabled, PHP checks whether the files or directories being operated upon have the same UID (owner) as the script that is being executed.
See Also
- 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