Xau(3)									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 spec‐
       ifies  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	autho‐
       rization 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 1.0.6				Xau(3)

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