(PHP 5 >= 5.1.0, PHP 7)

posix_access Determine accessibility of a file


posix_access ( string $file [, int $mode = POSIX_F_OK ] ) : bool

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



The name of the file to be tested.


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.

Zwracane wartości

Zwraca TRUE w przypadku powodzenia, FALSE w przypadku błędu.


Przykład #1 posix_access() example

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



if (
posix_access($filePOSIX_R_OK POSIX_W_OK)) {
'The file is readable and writable!';

} else {
$error posix_get_last_error();

"Error $error: " posix_strerror($error);



Informacja: Gdy włączony jest tryb bezpieczny, PHP sprawdza, czy pliki lub katalogi, na których zostaną wykonane operacje mają takie same UID (owner) jak skrypt, który jest aktualnie wykonywany.

Zobacz też:

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User Contributed Notes 1 note

unixguy at earth dot com
6 years ago
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.
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