NAME

access − determine accessibility of a file

SYNOPSIS

int access (path, amode)
char ∗path;
int amode;

DESCRIPTION

Path points to a path name naming a file.  Access checks the named file for accessibility according to the bit pattern contained in amode, using the real user ID in place of the effective user ID and the real group ID in place of the effective group ID.  The bit pattern contained in amode is constructed as follows:

04read
02write
01execute (search)
00check existence of file

RETURN VALUE

If the requested access is permitted, a value of 0 is returned.  Otherwise, a value of −1 is returned and errno is set to indicate the error. 

ERRORS

Access to the file is denied if one or more of the following are true:

[ENOTDIR] A component of the path prefix is not a directory. 

[ENOENT] Read, write, or execute (search) permission is requested for a null path name. 

[ENOENT] The named file does not exist. 

[EACCES] Search permission is denied on a component of the path prefix. 

[EROFS] Write access is requested for a file on a read-only file system. 

[ETXTBSY] Write access is requested for a pure procedure (shared text) file that is being executed. 

[EACCES] Permission bits of the file mode do not permit the requested access and the real user ID is not the super-user. 

[EFAULT] Path points outside the allocated address space for the process.  The reliable detection of this error will be implementation dependent. 

[ENAMETOOLONG] The named file exceeds MAXPATHLEN characters. 

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 permissions checked with respect to the “group” mode bits, and all others have permissions checked with respect to the “other” mode bits. 

Access will report that a file currently open for execution is not writable, regardless of the setting of its mode. 

HARDWARE DEPENDENCIES

Integral PC
Super-user capabilities are provided to the normal user.

A file currently open for execution is writeable. 

SEE ALSO

chmod(2), stat(2). 

Hewlett-Packard Company  —  Version B.1,  May 11, 2021