locate_task

Arguments

Returns

A task if successful, otherwise nil.

Description

This function makes a call to the name locator task for the current operating system. If it finds the named task it makes an IPC connection (in TCP/IP) or creates a virtual circuit (in QNX 4) to that task. If async_reqd is t, then init_async_ipc is also called.

When Gamma locates a task, it returns a printed representation of it, which looks like this: #<Task:10120>. This representation cannot be read back into Gamma, so a symbol is usually assigned when calling locate_task to facilitate refering to or working with a task. We refer to this symbol as the task descriptor. For instance, in the example below, the symbol tsk is the task descriptor.

Example

The two tasks are initiated with init_ipc before calling locate_task.

Task 1:

    Gamma> init_ipc("first","Q1");
    t
    Gamma> getpid();
    9231
    Gamma> tsk = locate_task("second",nil);
    #<Task:9092>
    Gamma> send (tsk, #princ("Are you there?\n"));
    t
    Gamma> 
    		

Task 2:

    Gamma> init_ipc("second","Q2");
    t
    Gamma> getpid();
    9092
    Gamma> next_event
    Are you there?
    t
    Gamma> 
    		

See the Starting Programs section of the Common Functions chapter (Tutorial One), or the Starting Programs section of the Common Functions for Any Program chapter (Tutorial Two), or the Common: Controlling the Cascade TextLogger section of the Log Functions chapter in the Cogent Tools Demo and Tutorials book for examples of this function used in context.

See Also

locate_task_id