posix_access Determine accessibility of a file php函数


(PHP 5 >= 5.1.0)

posix_access Determine accessibility of a file


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

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.


成功时返回 TRUE, 或者在失败时返回 FALSE.


Example #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);



Note: 当启用 安全模式时, PHP 会检查被操作的文件或目录是否与被执行的脚本有相同的 UID(所有者)。


posix_ctermid Get path name of controlling terminal
posix_errno 别名 posix_get_last_error
posix_getcwd Pathname of current directory
posix_getegid Return the effective group ID of the current process
posix_geteuid Return the effective user ID of the current process
posix_getgid Return the real group ID of the current process
posix_getgrgid Return info about a group by group id
posix_getgrnam Return info about a group by name
posix_getgroups Return the group set of the current process
posix_getlogin Return login name
posix_getpgid Get process group id for job control
posix_getpgrp Return the current process group identifier
posix_getpid Return the current process identifier
posix_getppid Return the parent process identifier

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