servers - Tool

Postscript file available

A tool for sending events between glish and precompiled executables

include "servers.g"

Description
servers communicates between glish distributed objects (tools) and C++ executables. It provides the following services:

Creation, execution and destruction of C++ servers
Parameter passing to and from servers
Plotting, progress meters, etc. (implemented in Glish or via a Glish layer)
Synchronous and asynchronous execution of functions
Logging of messages

There is only one servers tool running at any one time called defaultservers. This must be running if the tool system is to work at all.

Users normally need not interact with defaultservers. Its functions will largely be used by programmers writing tools and most of the interactions are hidden inside the tool framework (this is described in Note 197). The only major exceptions are:

When one wants to retrieve values returned by a function that was running asynchronously. This is described in the result function.
When one wants the name of a plotter used by a tool. This is returned by the getplotter function

The terminology used here needs some explanation:

server: A server is a C++ executable that runs as a process.
object: A server may contain one or more objects. An object is equivalent to a Glish tool. It usually has multiple functions that may be executed.

Some servers are pre-started to minimize AIPS++ startup time. The default pre-started clients are: timer, misc, and quanta. If you wish to prevent this, set the following in your .aipsrc file:

user.prestart:	none

If you wish to extend or change the list, set the following in your .aipsrc file:

user.prestart:	timer misc quanta measures

Integers are used to index into lists of servers and objects. Thus to specify a server requires one integer, and to specify an object requires two: one for the server and one for the object. Thus the functions of servers require one or both of these, depending on whether the operation is server or object-specific.

Constructors
Functions

activate	Create a new server
add	Add an object to an existing server
agents	Return a record of all agents
alerter	Relay events on completion
busy	Is the server busy?
create	Create an object
done	Delete a tool
getplotter	Get the plotter used by a tool
info	Print information on the existing servers.
init	Initialize servers
isvalid	Is this a valid server?
kill	Kill a given agent
memory	Return the memory usage of each server
methods	Return the methods of an object
result	Get the result(s) from an asynchronous function.
run	Run a function in an object
running	Determine if an asynchronous function is running
sendmemoryevents	Enable the generation of memory events
settimeout	Set event timeouts
stopmemoryevents	Disable the generation of memory events
suspend	Suspend certain clients
timeouts	Return record of timeouts
trace	Trace events related to certain clients

Next: servers.activate - Function Up: tasking - Module Previous: asynceval.done - Function Contents Index

	Package	utility
	Module	tasking