NAME

access − determine accessibility of a file

SYNOPSIS

#include <unistd.h>

int access(const 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 by an OR of the following constants (defined in <unistd.h>):

R_OKread
W_OKwrite
X_OKexecute (search)
F_OKcheck existence of file

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

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

EACCES Permission bits of the file mode do not permit the requested access. 

EFAULT path points outside the allocated address space for the process. 

EINTR A signal was caught during the access system call. 

EINVAL Argument is invalid. 

ELOOP Too many symbolic links were encountered in translating path.

EMULTIHOP Components of path require hopping to multiple remote machines. 

ENAMETOOLONG The length of the path argument exceeds {PATH_MAX}, or the length of a path component exceeds {NAME_MAX} while _POSIX_NO_TRUNC is in effect. 

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. 

ENOLINK path points to a remote machine and the link to that machine is no longer active. 

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

SEE ALSO

chmod(2), stat(2)
“File Access Permission” in intro(2). 

DIAGNOSTICS

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.