access - Determines the accessibility of a file
int access (
const char *path,
int access_mode) ;
Interfaces documented on this reference page conform to industry standards
access(): XPG4, XPG4-UNIX
Refer to the standards(5) reference page for more information about indus-
try standards and associated tags.
Points to the file pathname. When the path parameter refers to a sym-
bolic link, the access() function returns information about the file
pointed to by the symbolic link.
Permission to access all components of the path parameter is determined
by using a real user ID instead of an effective user ID, and a group
access list (including a real group ID) instead of an effective group
Specifies the type of access. The bit pattern contained in the
access_mode parameter is constructed by a logical OR of the following
R_OK Checks read permission.
W_OK Checks write permission.
X_OK Checks execute (search) permission.
F_OK Checks to see if the file exists.
The access() function checks for accessibility of the file specified by a
Only access bits are checked. A directory may be indicated as writable by
access(), but an attempt to open it for writing will fail (although files
may be created there); a file's access bits may indicate that it is execut-
able, but the execve() function can fail if the file does not contain the
Upon successful completion, the access() function returns value of 0
(zero). Otherwise, a value of -1 is returned and errno is set to indicate
If the access() function fails, access to the file specified by the path
parameter is denied and errno may be set to one of the following values:
[EACCES] Permission bits of the file mode do not permit the requested
access, or search permission is denied on a component of the path
prefix. The owner of a file has permission checked with respect
to the ``owner'' read, write, and execute mode bits, members of
the file's group other than the owner have permission checked
with respect to the ``group'' mode bits, and all others have per-
missions checked with respect to the ``other'' mode bits.
[EFAULT] The path parameter points outside the process' allocated address
[EINVAL] The pathname contains a character with the high-order bit set.
[EIO] An I/O error occurred while reading from or writing to the file
[ELOOP] Too many symbolic links were encountered in translating the path-
A component of a pathname exceeded PATH_MAX characters, or an
entire pathname exceeded NAME_MAX characters.
[ENOENT] The named file does not exist or is an empty string.
[ENOTDIR] A component of the path prefix is not a directory.
[EROFS] Write access is requested for a file on a read-only file system.
Functions: chmod(2), stat(2)