Linux and UNIX Man Pages

Test Your Knowledge in Computers #363
Difficulty: Medium
uudecode originated in Version 1 AT&T UNIX.
True or False?
Linux & Unix Commands - Search Man Pages

setxattr(2) [osx man page]

SETXATTR(2)						      BSD System Calls Manual						       SETXATTR(2)

NAME
setxattr, fsetxattr -- set an extended attribute value SYNOPSIS
#include <sys/xattr.h> int setxattr(const char *path, const char *name, void *value, size_t size, u_int32_t position, int options); int fsetxattr(int fd, const char *name, void *value, size_t size, u_int32_t position, int options); DESCRIPTION
Extended attributes extend the basic attributes associated with files and directories in the file system. They are stored as name:data pairs associated with file system objects (files, directories, symlinks, etc). setxattr() associates name and data together as an attribute of path. An extended attribute's name is a simple NULL-terminated UTF-8 string. Value is a pointer to a data buffer of size bytes containing textual or binary data to be associated with the extended attribute. Position specifies the offset within the extended attribute. In the current implementation, only the resource fork extended attribute makes use of this argument. For all others, position is reserved and should be set to zero. options controls how the attribute is set: XATTR_NOFOLLOW do not follow symbolic links. setxattr() normally sets attributes on the target of path if it is a symbolic link. With this option, setxattr() will act on the link itself. XATTR_CREATE fail if the named attribute already exists. XATTR_REPLACE fail if the named attribute does not exist. Failure to specify XATTR_REPLACE or XATTR_CREATE allows creation and replace- ment. fsetxattr() is identical to setxattr(), except that it sets an extended attribute on an open file referenced by file descriptor fd. NOTES
On some filesystems, such as HFS+, setting the extended attribute com.apple.ResourceFork will update the modification time (``mtime'') of the file. Due to historical reasons, the XATTR_FINDERINFO_NAME (defined to be ``com.apple.FinderInfo'') extended attribute must be 32 bytes; see the ATTR_CMN_FNDRINFO section in getattrlist(2). The maximum supported size of extended attribute can be found out using pathconf(2) with _PC_XATTR_SIZE_BITS option. RETURN VALUES
On success, 0 is returned. On failure, -1 is returned and the global variable errno is set as follows. ERRORS
[EEXIST] options contains XATTR_CREATE and the named attribute already exists. [ENOATTR] options is set to XATTR_REPLACE and the named attribute does not exist. [ENOTSUP] The file system does not support extended attributes or has them disabled. [EROFS] The file system is mounted read-only. [ERANGE] The data size of the attribute is out of range (some attributes have size restrictions). [EPERM] Attributes cannot be associated with this type of object. For example, attributes are not allowed for resource forks. [EINVAL] name or options is invalid. name must be valid UTF-8 and options must make sense. [ENOTDIR] A component of path is not a directory. [ENAMETOOLONG] name exceeded XATTR_MAXNAMELEN UTF-8 bytes, or a component of path exceeded NAME_MAX characters, or the entire path exceeded PATH_MAX characters. [EACCES] Search permission is denied for a component of path or permission to set the attribute is denied. [ELOOP] Too many symbolic links were encountered resolving path. [EFAULT] path or name points to an invalid address. [EIO] An I/O error occurred while reading from or writing to the file system. [E2BIG] The data size of the extended attribute is too large. [ENOSPC] Not enough space left on the file system. SEE ALSO
getxattr(2), listxattr(2), removexattr(2), pathconf(2) HISTORY
setxattr() and fsetxattr() first appeared in Mac OS X 10.4. Mac OS X Oct 19, 2004 Mac OS X

Check Out this Related Man Page

GETXATTR(2)						      BSD System Calls Manual						       GETXATTR(2)

NAME
getxattr, fgetxattr -- get an extended attribute value SYNOPSIS
#include <sys/xattr.h> ssize_t getxattr(const char *path, const char *name, void *value, size_t size, u_int32_t position, int options); ssize_t fgetxattr(int fd, const char *name, void *value, size_t size, u_int32_t position, int options); DESCRIPTION
Extended attributes extend the basic attributes of files and directories in the file system. They are stored as name:data pairs associated with file system objects (files, directories, symlinks, etc). The getxattr() function retrieves up to size bytes of data from the extended attribute identified by name associated with path into the pre- allocated buffer pointed to by value. The function returns the number of bytes of data retrieved. An extended attribute's name is a simple NULL-terminated UTF-8 string. position specifies an offset within the extended attribute. In the current implementation, this argument is only used with the resource fork attribute. For all other extended attributes, this parameter is reserved and should be zero. On success, value contains the data associated with name. When value is set to NULL, getxattr() returns current size of the named attribute. This facility can be used to determine the size of a buffer sufficiently large to hold the data currently associated with the attribute. options specify options for retrieving extended attributes: XATTR_NOFOLLOW do not follow symbolic links. getxattr() normally returns information from the target of path if it is a symbolic link. With this option, getxattr() will return extended attribute data from the symbolic link instead. XATTR_SHOWCOMPRESSION getxattr() and fgetxattr() will return HFS Plus Compression extended attribute name (if present) for the file referred to by path or fd. fgetxattr() is identical to getxattr(), except that it retrieves extended attribute data from the open file referenced by the file descriptor fd. RETURN VALUES
On success, the size of the extended attribute data is returned. On failure, -1 is returned and the global variable errno is set as follows. ERRORS
[ENOATTR] The extended attribute does not exist. [ENOTSUP] The file system does not support extended attributes or has the feature disabled. [ERANGE] value (as indicated by size) is too small to hold the extended attribute data. [EPERM] The named attribute is not permitted for this type of object. [EINVAL] name is invalid or options has an unsupported bit set. [EISDIR] path or fd do not refer to a regular file and the attribute in question is only applicable to files. Similar to EPERM. [ENOTDIR] A component of path 's prefix is not a directory. [ENAMETOOLONG] The length of name exceeds XATTR_MAXNAMELEN UTF-8 bytes, or a component of path exceeds NAME_MAX characters, or the entire path exceeds PATH_MAX characters. [EACCES] Search permission is denied for a component of path or the attribute is not allowed to be read (e.g. an ACL prohibits reading the attributes of this file). [ELOOP] Too many symbolic links were encountered in translating the pathname. [EFAULT] path or name points to an invalid address. [EIO] An I/O error occurred while reading from or writing to the file system. SEE ALSO
listxattr(2), removexattr(2), setxattr(2) HISTORY
getxattr() and fgetxattr() first appeared in Mac OS X 10.4. Mac OS X Oct 19, 2004 Mac OS X

Featured Tech Videos