listxattr, llistxattr, flistxattr – list extended attribute names

NAME

       listxattr, llistxattr, flistxattr - list extended attribute names

SYNOPSIS

       #include 
       #include 

       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);

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).

       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 simple null-terminated string.
       The name includes a namespace prefix; there may be several, disjoint
       namespaces associated with an individual inode.

       An empty buffer of size zero can be passed into these calls to return
       the current size of the list of extended attribute names, which can
       be used to estimate the size of a buffer which is sufficiently large
       to hold the list of names.

RETURN VALUE

       The list of names is returned as an unordered array of null-
       terminated character strings (attribute names are separated by null
       bytes ('ng>);
       unsigned char inb_p(unsigned short int port);
       unsigned short int inw(unsigned short int port);
       unsigned short int inw_p(unsigned short int port);
       unsigned int inl(unsigned short int port);
       unsigned int inl_p(unsigned short int port);

       void outb(unsigned char value, unsigned short int port);
       void outb_p(unsigned char value, unsigned short int port);
       void outw(unsigned short int value, unsigned short int port);
       void outw_p(unsigned short int value, unsigned short int port);
       void outl(unsigned int value, unsigned short int port);
       void outl_p(unsigned int value, unsigned short int port);

       void insb(unsigned short int port, void *addr,
                  unsigned long int count);
       void insw(unsigned short int port, void *addr,
                  unsigned long int count);
       void insl(unsigned short int port, void *addr,
                  unsigned long int count);
       void outsb(unsigned short int port, const void *addr,
                  unsigned long int count);
       void outsw(unsigned short int port, const void *addr,
                  unsigned long int count);
       void outsl(unsigned short int port, const void *addr,
                  unsigned long int count);

DESCRIPTION

       This family of functions is used to do low-level port input and
       output.  The out* functions do port output, the in* functions do port
       input; the b-suffix functions are byte-width and the w-suffix
       functions word-width; the _p-suffix functions pause until the I/O
       completes.

       They are primarily designed for internal kernel use, but can be used
       from user space.

       You must compile with -O or -O2 or similar.  The functions are
       defined as inline macros, and will not be substituted in without
       optimization enabled, causing unresolved references at link time.

       You use ioperm(2) or alternatively iopl(2) to tell the kernel to
       allow the user space application to access the I/O ports in question.
       Failure to do this will cause the application to receive a
       segmentation fault.

CONFORMING TO

       outb() and friends are hardware-specific.  The value argument is
       passed first and the port argument is passed second, which is the
       opposite order from most DOS implementations.

SEE ALSO

       ioperm(2), iopl(2)

COLOPHON

       This page is part of release 3.55 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                            2012-12-31                          OUTB(2)