Xau(3)                     Library Functions Manual                     Xau(3)

NAME
       Xau library: XauFileName, XauReadAuth, XauLockAuth, XauUnlockAuth,
       XauWriteAuth, XauDisposeAuth, XauGetAuthByAddr, XauGetBestAuthByAddr -
       X authority database routines

SYNOPSIS
       #include <X11/Xauth.h>

       typedef struct xauth {
               unsigned short  family;
               unsigned short  address_length;
               char    *address;
               unsigned short  number_length;
               char    *number;
               unsigned short  name_length;
               char    *name;
               unsigned short  data_length;
               char    *data;
       } Xauth;

       char *XauFileName (void);

       Xauth *XauReadAuth (FILE *auth_file);

       int XauWriteAuth (FILE *auth_file, Xauth *auth);

       Xauth *XauGetAuthByAddr (unsigned short family, unsigned short
              address_length, const char *address, unsigned short
              number_length, const char *number, unsigned short
              name_length, const char *name);

       Xauth *XauGetBestAuthByAddr (unsigned short family, unsigned short
              address_length, const char *address, unsigned short
              number_length, const char *number, int types_length,
              char **types, const int *type_lengths);

       int XauLockAuth (const char *file_name, int retries, int
              timeout, long dead);

       int XauUnlockAuth (const char *file_name);

       int XauDisposeAuth (Xauth *auth);

DESCRIPTION
       XauFileName generates the default authorization file name by first
       checking the XAUTHORITY environment variable if set, else it returns
       $HOME/.Xauthority.  This name is statically allocated and should not be
       freed.

       XauReadAuth reads the next entry from auth_file.  The entry is not
       statically allocated and should be freed by calling XauDisposeAuth.

       XauWriteAuth writes an authorization entry to auth_file.  It returns 1
       on success, 0 on failure.

       XauGetAuthByAddr searches for an entry which matches the given network
       address/display number pair.  The entry is not statically allocated and
       should be freed by calling XauDisposeAuth.

       XauGetBestAuthByAddr is similar to XauGetAuthByAddr, except that a list
       of acceptable authentication methods is specified.  Xau will choose the
       file entry which matches the earliest entry in this list (e.g., the
       most secure authentication method).  The types argument is an array of
       strings, one string for each authentication method.  types_length
       specifies how many elements are in the types array.  types_lengths is
       an array of integers representing the length of each string.

       XauLockAuth does the work necessary to synchronously update an
       authorization file.  First it makes two file names, one with ``-c''
       appended to file_name, the other with ``-l'' appended.  If the ``-c''
       file already exists and is more than dead seconds old, XauLockAuth
       removes it and the associated ``-l'' file.  To prevent possible
       synchronization troubles with NFS, a dead value of zero forces the
       files to be removed.  XauLockAuth makes retries attempts to create and
       link the file names, pausing timeout seconds between each attempt.
       XauLockAuth returns a collection of values depending on the results:

       LOCK_ERROR
              A system error occurred, either a file_name which is too long,
              or an unexpected failure from a system call.  errno may prove
              useful.

       LOCK_TIMEOUT
              retries attempts failed

       LOCK_SUCCESS
              The lock succeeded.

       XauUnlockAuth undoes the work of XauLockAuth by unlinking both the
       ``-c'' and ``-l'' file names.

       XauDisposeAuth frees storage allocated to hold an authorization entry.

SEE ALSO
       xauth(1), xdm(1)

AUTHOR
       Keith Packard, MIT X Consortium

X Version 11                     libXau 1.0.9                           Xau(3)