JPH05143271A - Screen switching control system - Google Patents

Abstract

PURPOSE:To improve screen switching control by providing one managing task which manages plural tasks systematically in a system where only one screen of an information processor is shared with the plural tasks. CONSTITUTION:When a control task 1 for screen switching, a task 2 to request the screen switching, a task 3 capable of performing screen display until then, and a task 4 capable of performing the screen display hereafter exist, a state where the screen display can be performed is called as active, and a state to suppress the display as hold. The task 1 receives a screen switching request from the task 2, and sends a hold request to the task 3, and sends an active request to the task 4 after receiving hold completion information from the task 3. Furthermore, the task 1 receives active completion information from the task 4, and sends screen switching completion information to the task 2. Also, the task 1 is always controlled so as not to send the hold request and the active request in duplication to the task set in a hold state or active state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for controlling screen display and screen switching of a multitasking program in an information processing system.

[0002]

2. Description of the Related Art Conventionally, this type of screen switching is a control closed in one program, and screens are created so as to be switched according to a predetermined screen transition procedure. In the case of a multitasking system that executes multiple independent programs in parallel, a method to prevent multiple tasks from being displayed simultaneously on one screen by dividing the tasks into those that display the screen and those that do not There is a method of dividing the screen and allocating a portion that can be used for display for each task.

[0003]

The above-mentioned conventional method has a drawback that fixed screen switching cannot be performed because the screen is switched according to a predetermined screen transition procedure. In addition, since only one screen can be controlled by one program, if you want to make a multi-task system, you have to divide it into tasks that display the screen and tasks that do not display the screen, or divide the screen and assign it to each task fixedly It has the drawback of not becoming.

It is an object of the present invention to provide a screen switching control system which improves the above-mentioned drawbacks by providing one management task for managing a plurality of tasks in a unified manner.

[0005]

According to the screen switching control method of the present invention, in a system in which a plurality of tasks share a single screen of an information processing device, one management task is used as a subordinate task by using inter-task communication. The screen display of one task is always executed and the screen display of other tasks is suppressed.

[0006]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is an explanatory view showing an embodiment of the present invention. In the figure, the screen switching control method includes a screen switching control task 1 and a screen switching task 2
And a task 3 that can be displayed on the screen until now and a task 4 that can be displayed on the screen. Hereinafter, the screen switching control procedure will be abbreviated as active and the screen display suppression state as a hold, and the procedure of screen switching control will be described for each task.

[0008] Task 1 receives a screen switching request notification from task 2, sends a hold request notification to task 3, receives a hold completion notification from task 3, and then sends an active request notification to task 4. Further, it receives an active completion notification from task 4, and sends a screen switching completion notification to task 2. Further, the task 1 always keeps track of active tasks, and does not send hold request notifications or active request notifications to the held or active tasks twice. As described above, the task 1 has a role as the only management task in this screen switching control method.

Upon receiving the hold request notification, task 3 does not display the subsequent screen display on the actual screen but writes it in the save area on the memory. Further, the task 3 sends a hold completion notice to the task 1 to inform that the hold state has been changed from the active state.

Upon receiving the active request notification, task 4 displays the screen display data saved in the hold state on the actual screen. Then, the subsequent screen display is output to both the actual screen and the save area on the memory. Also, task 4 sends an active completion notification to task 1
To notify that the transition from the hold state to the active state is completed.

Task 2 is a task for requesting screen switching, and sends a screen switching request to task 1 and waits until a result notification is received from task 1. When the task 2 is in the active state, the screen switching request is sent to the task 1 after shifting to the hold state.

When the task in the active state makes a screen switching request, task 1 sends only the active request notification without sending the hold request notification.

[0013]

As described above, the present invention provides a screen display device having only one management task, having communication between tasks, and having a screen save area on the memory. It can be shared among multiple tasks.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention.

[Explanation of symbols]

 1 Screen switching control task 2 Task requesting screen switching 3 Task that could be displayed on the screen 4 Task that can be displayed on the screen

Claims (1)

[Claims] 1. In a system in which a plurality of tasks share a single screen of an information processing device, one management task always executes screen display of one task among subordinate tasks by using inter-task communication, and other tasks. Screen switching control method characterized by suppressing the screen display of the task.