NAME

access - determine accessibility of a file

SYNOPSIS

#include <unistd.h>

int access(const char * path, int amode);

MT-LEVEL

Async-Signal-Safe

DESCRIPTION

access( ) checks the file pointed to by path 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 .This allows a setuid process to verify that the user running it would have had permission to access this file. The bit pattern contained in amode is constructed by an OR of the access permissions to be checked (R_OK, W_OK, and X_OK, or the existence test, (F_OK). These constants are defined in <unistd.h> as follows:

R_OK Test for read permission.

W_OK Test for write permission.

X_OK

Test for execute or search permission.

F_OK

Check existence of file

See intro(2) for additional information about "File Access Permission".

RETURN VALUES

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:

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 to an illegal address.

EINTR

A signal was caught during the access( ) function.

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.

ENOENT

The path argument points to an empty string or to the name of a file that does not exist.

ENOLINK

path points to a remote machine and the link to that machine is no longer active.

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.

SEE ALSO

intro(2), chmod(2), stat(2)