LISTXATTR(2) Linux Programmer's Manual LISTXATTR(2)
listxattr, llistxattr, flistxattr - list extended attribute names
ssize_t listxattr(const char *path, char *list, size_t size);
ssize_t llistxattr(const char *path, char *list, size_t size);
ssize_t flistxattr(int fd, char *list, size_t size);
Extended attributes are name:value pairs associated with inodes (files, directories, symbolic links, etc.). They are extensions to the
normal attributes which are associated with all inodes in the system (i.e., the stat(2) data). A complete overview of extended attributes
concepts can be found in attr(5).
listxattr() retrieves the list of extended attribute names associated with the given path in the filesystem. The retrieved list is placed
in list, a caller-allocated buffer whose size (in bytes) is specified in the argument size. The list is the set of (null-terminated)
names, one after the other. Names of extended attributes to which the calling process does not have access may be omitted from the list.
The length of the attribute name list is returned.
llistxattr() is identical to listxattr(), except in the case of a symbolic link, where the list of names of extended attributes associated
with the link itself is retrieved, not the file that it refers to.
flistxattr() is identical to listxattr(), only the open file referred to by fd (as returned by open(2)) is interrogated in place of path.
A single extended attribute name is a null-terminated string. The name includes a namespace prefix; there may be several, disjoint names-
paces associated with an individual inode.
If size is specified as zero, these calls return the current size of the list of extended attribute names (and leave list unchanged). This
can be used to determine the size of the buffer that should be supplied in a subsequent call. (But, bear in mind that there is a possibil-
ity that the set of extended attributes may change between the two calls, so that it is still necessary to check the return status from the
The list of names is returned as an unordered array of null-terminated character strings (attribute names are separated by null bytes