Visit The New, Modern Unix Linux Community

Linux and UNIX Man Pages

Test Your Knowledge in Computers #722
Difficulty: Medium
Konrad Zuse built the first digital freely programmable computer, the Z1.
True or False?
Linux & Unix Commands - Search Man Pages

getxattr(2) [linux man page]

GETXATTR(2)						     Linux Programmer's Manual						       GETXATTR(2)

NAME
getxattr, lgetxattr, fgetxattr - retrieve an extended attribute value SYNOPSIS
#include <sys/types.h> #include <sys/xattr.h> ssize_t getxattr(const char *path, const char *name, void *value, size_t size); ssize_t lgetxattr(const char *path, const char *name, void *value, size_t size); ssize_t fgetxattr(int fd, const char *name, void *value, size_t size); DESCRIPTION
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). getxattr() retrieves the value of the extended attribute identified by name and associated with the given path in the filesystem. The attribute value is placed in the buffer pointed to by value; size specifies the size of that buffer. The return value of the call is the number of bytes placed in value. lgetxattr() is identical to getxattr(), except in the case of a symbolic link, where the link itself is interrogated, not the file that it refers to. fgetxattr() is identical to getxattr(), only the open file referred to by fd (as returned by open(2)) is interrogated in place of path. An extended attribute name is a null-terminated string. The name includes a namespace prefix; there may be several, disjoint namespaces associated with an individual inode. The value of an extended attribute is a chunk of arbitrary textual or binary data that was assigned using setxattr(2). If size is specified as zero, these calls return the current size of the named extended attribute (and leave value 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 possibility that the attribute value may change between the two calls, so that it is still necessary to check the return status from the second call.) RETURN VALUE
On success, these calls return a nonnegative value which is the size (in bytes) of the extended attribute value. On failure, -1 is returned and errno is set appropriately. ERRORS
ENOATTR The named attribute does not exist, or the process has no access to this attribute. (ENOATTR is defined to be a synonym for ENODATA in <attr/xattr.h>.) ENOTSUP Extended attributes are not supported by the filesystem, or are disabled. ERANGE The size of the value buffer is too small to hold the result. In addition, the errors documented in stat(2) can also occur. VERSIONS
These system calls have been available on Linux since kernel 2.4; glibc support is provided since version 2.3. CONFORMING TO
These system calls are Linux-specific. EXAMPLE
See listxattr(2). SEE ALSO
getfattr(1), setfattr(1), listxattr(2), open(2), removexattr(2), setxattr(2), stat(2), attr(5), symlink(7) Linux 2015-02-21 GETXATTR(2)

Check Out this Related Man Page

GETXATTR(2)						     Linux Programmer's Manual						       GETXATTR(2)

NAME
getxattr, lgetxattr, fgetxattr - retrieve an extended attribute value SYNOPSIS
#include <sys/types.h> #include <attr/xattr.h> ssize_t getxattr(const char *path, const char *name, void *value, size_t size); ssize_t lgetxattr(const char *path, const char *name, void *value, size_t size); ssize_t fgetxattr(int fd, const char *name, void *value, size_t size); DESCRIPTION
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). getxattr() retrieves the value of the extended attribute identified by name and associated with the given path in the file system. The length of the attribute value is returned. lgetxattr() is identical to getxattr(), except in the case of a symbolic link, where the link itself is interrogated, not the file that it refers to. fgetxattr() is identical to getxattr(), only the open file referred to by fd (as returned by open(2)) is interrogated in place of path. An extended attribute name is a simple null-terminated string. The name includes a namespace prefix; there may be several, disjoint names- paces associated with an individual inode. The value of an extended attribute is a chunk of arbitrary textual or binary data of specified length. An empty buffer of size zero can be passed into these calls to return the current size of the named extended attribute, which can be used to estimate the size of a buffer which is sufficiently large to hold the value associated with the extended attribute. The interface is designed to allow guessing of initial buffer sizes, and to enlarge buffers when the return value indicates that the buffer provided was too small. RETURN VALUE
On success, a positive number is returned indicating the size of the extended attribute value. On failure, -1 is returned and errno is set appropriately. If the named attribute does not exist, or the process has no access to this attribute, errno is set to ENOATTR. If the size of the value buffer is too small to hold the result, errno is set to ERANGE. If extended attributes are not supported by the file system, or are disabled, errno is set to ENOTSUP. The errors documented for the stat(2) system call are also applicable here. VERSIONS
These system calls have been available on Linux since kernel 2.4; glibc support is provided since version 2.3. CONFORMING TO
These system calls are Linux-specific. SEE ALSO
getfattr(1), setfattr(1), listxattr(2), open(2), removexattr(2), setxattr(2), stat(2), attr(5), symlink(7) COLOPHON
This page is part of release 3.25 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/. Linux 2001-12-01 GETXATTR(2)

Featured Tech Videos