access(2)access(2)NAMEaccess - Determines the accessibility of a file
const char *path,
int access_mode );
Interfaces documented on this reference page conform to industry stan‐
dards as follows:
access(): XSH4.0, XSH4.2, XSH5.0
Refer to the standards(5) reference page for more information about
industry 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 ID. Specifies the type of access. The bit
pattern contained in the access_mode parameter is constructed by
a logical OR of the following values: Checks read permission.
Checks write permission. Checks execute (search) permission.
Checks to see if the file exists.
The access() function checks for accessibility of the file specified by
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 executable, but the execve() function can fail if the file does not
contain the proper format.
The access() function is supported for multi-threaded applications.
Upon successful completion, the access() function returns value of 0
(zero). Otherwise, a value of -1 is returned and errno is set to indi‐
cate the error.
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: Permission bits of the file mode do not permit the requested
access, or search permission is denied on a component of the path pre‐
fix. The owner of a file has permission checked with respect to the
``user'' 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 permissions checked with
respect to the ``other'' mode bits. The path parameter points outside
the allocated address space of the process. [Tru64 UNIX] The pathname
contains a character with the high-order bit set. [Tru64 UNIX] An I/O
error occurred while reading from or writing to the file system. Too
many symbolic links were encountered in translating the pathname. A
component of a pathname exceeded PATH_MAX characters, or an entire
pathname exceeded NAME_MAX characters. The named file does not exist
or is an empty string. A component of the path prefix is not a direc‐
tory. Write access is requested for a file on a read-only file system.
Functions: chmod(2), stat(2)eaccess(3)