NAME

       XPATemplate -  Access Point Names and Templates

SYNOPSIS

       XPA access points are composed of two parts: a general class and a specific name.  Both
       parts accept template characters so that you can send/retrieve data to/from multiple
       servers at one time.

DESCRIPTION

       When XPA servers call XPANew(), or XPACmdNew() to define XPA access points, they specify a
       string identifier composed of a class and a name. When clients communicate with XPA access
       points, they specify which access points to communicate with using an identifier of the
       form:

         class:name

       All registered XPA access points that match the specified identifier will be available for
       communication (subject to access control rules, etc.)

       As of XPA 2.1.5, the length of both the class and name designations are limited to 1024
       characters.

       The XPA class:name identifier actually is a template: it accepts wild cards in its syntax,
       so a single specifier can match more than one XPA access point.  (Note that the class is
       optional and defaults to "*".)  The allowed syntax for clients to specify the class:name
       template is of the form shown below. (Note that "*" is used to denote a generic wild card,
       but other wild cards characters are supported, as described below).

         template      explanation
         --------      -----------
         class:name    exact match of class and name
         name          match any class with this name
         *:name        match any class with this name
         class:*       match any name of this class
         *:*           match any access point

       In general, the following wild-cards can be applied to class and name:

         wildcard      explanation
         --------      -----------
         ?             match any character, but there must be one
         *             match anything, or nothing
         [...]         match an inclusive set

       Although the class:name template normally is used to refer to XPA access points, these
       also can be specified using their individual socket identifiers.  For inet sockets, the
       socket identifier is ip - port, where ip can be the DNS-registered name, the ASCII IP
       number (e.g. 123.45.67.890) or the hex IP number (e.g. 838f3a60). For unix sockets, the
       identifier is the socket file name.  These socket identifiers are displayed as the fourth
       argument in the xpans display of registered access points.  For example, consider the ds9
       program started using inet sockets. The xpans name server will register something like
       this:

         csh> xpaget xpans
         DS9 ds9 gs saord.harvard.edu:3236 eric

       You can access ds9 using ip:3236 in any of the three forms:

         csh> xpaget saord:3236 file
         /home/eric/data/snr.ev

         csh> xpaget 123.45.67.890:3236 file
         /home/eric/data/snr.ev

         csh> xpaget 838f3a60:3236 file
         /home/eric/data/snr.ev

       In the case of unix  sockets, the socket identifier is a file:

         csh> xpaget xpans
         DS9 ds9 gs /tmp/.xpa/DS9_ds9.2631 eric

         csh> xpaget /tmp/.xpa/DS9_ds9.2631 file
         /home/eric/data/snr.ev

       This feature can be useful in distinguishing between multiple instances of a program that
       all have the same class:name designation.

SEE ALSO

       See xpa(7) for a list of XPA help pages