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access(2) [ultrix man page]

access(2)							System Calls Manual							 access(2)

Name
       access - determine the accessibility of file

Syntax
       #include <unistd.h>
       accessible = access(path, mode)
       int accessible;
       char *path;
       int mode;

Description
       The  system  call,  checks the given file path for accessibility according to mode.  The argument mode is an inclusive OR of the bits R_OK,
       W_OK, and X_OK.	Specifying the argument mode as F_OK tests whether the directories leading to the file can be  searched  and  whether  the
       file exists.

       The  real  user	ID and the group access list (including the real group ID) are used to verify permissions.  This call is useful to set-UID
       programs.

       Note that only access bits are checked.	The call may indicate that a directory is writeable, but an attempt to open the  directory  fails,
       although files are present in the directory.  Additionally, a file may appear to be executable, but fails unless the file is in proper for-
       mat.

       If a path cannot be found, or if the desired access modes are not granted, a -1 value is returned; otherwise, a 0 value is returned.

Diagnostics
       Access to the file is denied if any of the following is true:

       [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's read, write, and execute mode bits.
		      Members of the file's group, other than the owner, have permission checked with respect to the group's mode bits.  All  oth-
		      ers have permissions checked with respect to the other mode bits.

       [EFAULT]       The path points outside the process's allocated address space.

       [EIO]	      An I/O error occurred while reading from or writing to the file system.

       [ELOOP]	      Too many symbolic links were encountered in translating the pathname.

       [ENAMETOOLONG] A path component length exceeds 255 characters or the length of path exceeds 1023 characters.

       [ENOENT]       The  file  referred  to by path does not exist or the path points to an empty string and the environment defined is POSIX or
		      SYSTEM_FIVE.

       [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.

       [ESTALE]       The file handle given in the argument was invalid.  The file referred to by that file handle no longer exists  or  has  been
		      revoked.

       [ETIMEDOUT]    A  connect  request or remote file operation fails because the connected party did not respond after a period of time deter-
		      mined by the communications protocol.

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

See Also
       chmod(2), stat(2)

																	 access(2)

Check Out this Related Man Page

access(2)							System Calls Manual							 access(2)

NAME
access - Determines the accessibility of a file SYNOPSIS
#include <unistd.h> int access ( const char *path, int access_mode) ; STANDARDS
Interfaces documented on this reference page conform to industry standards as follows: access(): XPG4, XPG4-UNIX Refer to the standards(5) reference page for more information about industry standards and associated tags. PARAMETERS
Points to the file pathname. When the path parameter refers to a symbolic 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. DESCRIPTION
The access() function checks for accessibility of the file specified by a pathname. 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. RETURN VALUES
Upon successful completion, the access() function returns value of 0 (zero). Otherwise, a value of -1 is returned and errno is set to indicate the error. ERRORS
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 ``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 permissions checked with respect to the ``other'' mode bits. The path parameter points outside the process' allocated address space. The pathname contains a char- acter with the high-order bit set. 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 directory. Write access is requested for a file on a read-only file system. RELATED INFORMATION
Functions: chmod(2), stat(2) Standards: standards(5) delim off access(2)
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