JP2000200198A - Inter-process communication system and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide inter-process communication capable of making a message itself perform intellectual behavior. SOLUTION: The message is sent from a process A210 which is a transmission origin to a process B230 which is a transmission destination. In this case, the process A210 selects a transmission process provided with a desired function from the transmission processes 242, 244 and 246, etc., provided with various functions prepared by an OS. Then, to a selected transmission process C220, a message main body 222 is sent by using a function (send message) provided by the OS. The process C220 which receives it performs a specified processing stipulated in the process C220 to communication contents. The process B230 which is the transmission destination receives the communication contents after receiving the processing intrinsic to the process C220 from the process C220 by using the function (receive message) provided by the OS. Also, the transmission processes 242, 244 and 246 are prepared not only by the OS but also by a user originally.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
It relates to inter-process communication in a system.

[0002]

2. Description of the Related Art In a multi-process system on a computer system, for example, UNIX, a process A
When trying to share information between the process B and
Communication between processes via shared memory. This will be described with reference to FIGS.

FIG. 1 shows a hardware configuration of a computer system on which a multi-process system is constructed. In this figure, a CPU 10 has a memory 30
And executes a program such as an OS for performing multi-process control and the like stored therein. This allows computers and
Controls the entire system. The computer system also includes peripheral devices 40 such as a hard disk, a monitor, and a keyboard.

FIG. 2 is a diagram for explaining a case where a message is transmitted from a process A 110 as a transmission source to a process B 130 as a transmission destination. In this case, the process A is executed in the shared memory 1 which is an area in the memory 30 in FIG.
20, the communication content 122 is written. The process B 130 that is the transmission destination reads the communication content 122 written from the shared memory 120. Thus, process A
Performs inter-process communication with process B.

[0005] When inter-process communication is performed via such a shared memory, a process A 110 to a process B 13
Since the communication content 122 written to the shared memory by the process A is received as it is, only the information can be transmitted. For this reason, the functions are very limited. In the inter-process communication in UNIX, there is a communication method using a message queue or a socket in addition to the shared memory.
They are the same in that they can only "transmit information".

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to make an intellectual behavior of a message itself such as, for example, "automatically rewrite own information according to the type of process of an information receiver". Is to provide interprocess communication.

[0007]

In order to achieve the above object, the present invention provides an inter-process communication system in a multi-process system in which processing is performed by a plurality of processes. And a processing unit for processing the passed message in the activated transmission process, and a transmission process check for checking whether there is a message addressed to itself by checking the transmission process. Means and a receiving means for receiving a message when there is a message addressed to the user.

As described above, by using the transmission process having the processing capability of the present invention, the message itself such as "automatically rewrite own information according to the type of the process of the information receiver" is provided. Behavior. In addition, by using a plurality of transmission processes having various functions, a system having flexibility can be constructed without changing a program that has already been created.

The transmission process is started as a child process of the transmission source process, and after receiving the message,
By operating as a child process of the destination process, the destination process can easily recognize that there is a message addressed to itself. Also, when a message is passed to the transmission process, by setting the current time of the designated transmission destination process, it is possible to synchronize with the transmission destination process. Note that the present invention also includes a method performed by the system of the present invention and a recording medium storing a program capable of constructing the system of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will be described in detail with reference to the drawings. The outline of the present invention will be described with reference to FIG.
The hardware configuration may be the same as that described with reference to FIG. FIG. 3A shows that a message is sent from a process A 210 as a transmission source to a process B as a transmission destination. In this case, as shown in FIG. 3B, the process A is a transmission process having a desired function from among the transmission processes 242, 244, 246 having various functions prepared by the OS. select. Then, for the selected transmission process (process C) 220, the communication content (message body) 222 is converted into a function (sen) provided by the OS.
dMessage). Process C220 received
Performs a specific process defined in the process C on the communication contents. The process B230 that is the transmission destination is the OS
Process (receiveMessage) provided by
The communication content 222 after receiving the process unique to the process C is received from 220. Note that the transmission process is not limited to the process prepared in the OS, and may be created by the user.

The transmission process has the same configuration as a normal process, and when it is created, it is necessary to describe, for example, a process when activated, a process for a message, a process to be performed at the time of termination, and the like.

The inter-process communication of the present invention shown in FIG.
This will be described in detail with reference to FIGS. FIG. 4 shows a transmission source process (process A) 210, a transmission process (process C) 220, a transmission destination process (process B) 230,
It is a figure for explaining mutual relation with S260. FIG. 5 shows a transmission source process (process A) 210 and an OS
5 is a flowchart for explaining a process for transmission performed in step (a). FIG. 6 shows a transmission process (process C) 22.
FIG. 7 is a diagram showing in detail a configuration of a message created by the process No. 0; FIG. 7 shows the transmission destination process (process B) 230 and O
It is a flowchart explaining the process for transmission performed in S.

In FIG. 4, a process B2 as a transmission destination
The process A 210 that sends a message to the OS 30 prepares a message 212 to be sent, and
Call the ndMessage function (Fig. 4). Called sen
The dMessage function activates the selected transmission process, Process C (FIG. 4), and copies a message to the activated process C (FIG. 4). A detailed processing flow at this time will be described with reference to FIG. 5, and a configuration example of a message created in the process C will be described with reference to FIG.

In FIG. 5, when transmitting a message, a process A which is a transmission source specifies a "head address of a message body", a "size of a message body", a "process ID of a transmission destination", and a process to be transmitted. The sendMessage function of the OS is called using the "program name of the message transmission process" for the argument as an argument (S50).
2).

The called sendMessage function first checks the contents of the argument from the process A of the transmission source (S5).
52) If it is an error, the called function ends abnormally and returns an error code to the calling process A as a return value (S564). In the process A, the return value is checked (S504), and if it is an error code, an error process corresponding to the error code is performed (S50).
8).

If the call has been made normally (S5
In Good at 52, the message transmission process specified by the transmission source process is started as a child process having the transmission source process (process A) as a parent (S55).
4). At this time, the memory size required by the activated transmission process is the sum of the size of the message body specified by the argument and the memory size required for activation.

Next, a flag indicating that the started process is the "message transfer process" is set at a predetermined position corresponding to this transfer process in the process management information of the OS (S556). Thereby, in the process management of the OS, the started process can be identified as the transmission process.

A message header is created and the message body is copied in an area in the transmission process using the arguments and the like specified in the process A (S55).
8). The data structure of the message created in this transmission process will be described in detail with reference to FIG. As shown in FIG. 6, the message 222 created in the process C, which is the transmission process shown in FIG. 4, is mainly composed of a header section 310 and a message body 340. The header section includes, for example, “header size” 312,
When processing is performed on a plurality of message types, a “message type” 314, a message transmission process ID 316 for specifying the selected transmission process, a “source process ID” 318 indicating the transmitted process A, a transmission destination "Destination process ID" 3 indicating the process B that is
20, “time of destination process at the moment of transmission” 322 for synchronizing processing, “message size” 32
4 and so on. The message body 340 can be freely set by the user (process).

Here, the "time of the destination process at the moment of transmission" 322 will be further described. This is to read the current time of the process B, which is the transmission destination, and set the time when the header part is created by the argument from the process A. Thereby, the process B which is the transmission destination
Can be synchronized by comparing it with their current time. For example, when this processing is applied to a computer game, the processing of the game operates in synchronization with creation of one frame of the screen, and one frame is recognized as having the same system time. Therefore, when process A sends a message to process B, whether process B can receive the message in the same frame depends on the order of processing of process A and process B (generally undefined unless explicitly specified), or There is a possibility that the process cannot be synchronized because it is not known whether it is one frame late. Therefore, basically 1
A mechanism for ensuring that the process B receives the message is required so that the message arrives with a frame delay, that is, at the start of the process of the process B in the next frame to which the process A has sent the message. For this synchronization processing, the “time of the process at the transmission destination at the moment of transmission” can be used.

Returning to the flowchart of FIG.
Is changed to a child process having process B, which is the transmission destination, as a parent (S560). As a result, the process B can directly access the process C, which is its own child process. With this, the sendMessage function of the OS ends normally (S562). When the sendMessage function ends normally, sen
Since the return value to the process A that called the dMessage function is not an error code (No in S504), the processing of the message in the process A ends normally (S50).
6).

Returning to FIG. 4, in this figure, process C220 has now been activated, into which message 222 has been copied. Process C, which is a transmission process, independently performs the process defined in this process on the copied message (FIG. 4).

The process B230, which is the transmission destination,
Using 60 checkMessage function (FIG. 4), it is checked whether a message for itself is sent (FIG. 4). If you have a message for yourself, OS260
The received message function is used to copy the message to its own area (FIG. 4). Then, the process B 230 can process the sent message 232. The processing at this time will be described in detail with reference to the flowchart of FIG.

In FIG. 7, process B, which is the destination process, first checks whether there is a message for itself.
Check by calling the checkMessage function of the OS (S70)
2). In the called checkMessage function (S750), a transfer process is searched for from the child process having the process B that called the checkMessage function as a parent, and a message to be received by the process B is checked (S75).
2). At this time, usually, a search time is not required because a list of only the transmission process is prepared. This routine (ch
The eckMessage function) ends (S754).

The calling process B checks the return value, and if there is no message to be transmitted, terminates normally (S
712), and the message transmission process ends. If there is a message, the type (type) of the message is checked to determine the copy destination of the content (S704). At this time, if the message cannot be read by the user, abnormal termination (S
714), and the process proceeds to an error process. If it can be read, the receiveMessage function of the OS is called with the start address (pointer) of the determined copy destination as an argument (S
706), receive the message.

The called receiveMessage function (S77)
0) copies the communication content (message body) to the area specified by the pointer of the argument of the destination process (process B) (S772). The process B that has called the receiveMessage function performs processing using the copied message (S708). If there is still a message to be processed (NO in S710), a process for receiving the message is performed again (S704). If all the messages have been read (YES in S710), the message transmission processing ends normally (S710).

The called receiveMessage function kills the transmission process (process C) every time the transmission of each message is completed (S774).
The error processing at the time of abnormal termination (S714) includes:
For example, a message to the effect that the message could not be read correctly may be issued (answered) to the process A that is the transmission source. You can also ignore this unreadable message.

By using such a message transmission process having a brain, a message can be processed, so that various applications can be considered. For example, in the message transmission process, it is possible to determine and change the transmission destination based on the information using the information on the transmission source of the message and the contents of the message body. Therefore, when it is necessary to send a message to a plurality of processes, the message transmission process can transmit the message by making its own copy and making the copy a child process of each transmission destination.

Further, since the content of the message can be rewritten in the message transmission process, the message can be changed according to the receiving method and format of the transmission destination. This allows the sending process to
A message can be sent without knowing the type or type of the process to which it is sent.

In the message transmission process, the time until the message arrives can be adjusted. Using this, it is possible to realize a message such as a time bomb that introduces the concept of time that reaches a partner after a certain period of time from the transmission of the message.

An active message having a role other than delivering a message can be realized using the message transfer process. For example, if it is determined that it takes time to transmit a message to a destination, a picture or character is displayed on the screen, or a sound is output from the speaker from when the message is transmitted at the source until the message arrives. Can be issued.

One example of various applications is shown in FIG.
This will be described in detail with reference to FIG. In FIG. 8, process B4
Reference numeral 30 denotes a process for managing the brightness of the screen, and process A410 is a process for requesting the process B430 to control the brightness. This request is made in process C420, which is the above-described message transmission process. The process of managing the brightness has a function of receiving a message defining the brightness of the screen and controlling the screen to the brightness. In this case, there are various types of transmission processes for transmitting the brightness control.
20 is fade-out (control to gradually darken the screen)
Is a communication process that can be realized.

In the process A410, the "first brightness", the "last brightness", and the "time" until the fade-out is completed are passed to the process 420 for transmitting the fade-out as a message. The message is read in the passed process 420 where the message was passed, thereby calculating the frame-by-frame brightness to fade out, for example, after 5 seconds. And
The brightness of each frame is transmitted as a message to the process B430 for managing the brightness of the screen for each frame. Thereby, fade-out can be realized. By using the transmission process of the present invention, it is possible to control various screen brightnesses by changing the transmission process without changing the process of managing the screen brightness.

As described above, by using the message transmission process having the brain of the present invention, a flexible system can be constructed without changing a program created in the past.

The present invention may be applied to, for example, a multi-processor system comprising a plurality of processors. The configuration of the present invention can be realized by reading and executing the program from the storage medium storing the program related to the process of the inter-process communication of the present invention by the system. The recording medium includes a floppy disk, a CD-ROM, a magnetic tape, a ROM cassette, and the like.

[0035]

As described above, according to the present invention, it is possible to provide an inter-process communication capable of causing an intellectual behavior of a message itself, and a flexible system can be constructed by using the inter-process communication. can do.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a hardware configuration of a computer system.

FIG. 2 is an explanatory diagram of conventional inter-process communication.

FIG. 3 is a schematic explanatory diagram of inter-process communication of the present invention.

FIG. 4 is an explanatory diagram of inter-process communication of the present invention.

FIG. 5 is a flowchart showing a process between a transmission source process and a transmission process.

FIG. 6 is a diagram showing a data structure of a message created in a transmission process.

FIG. 7 is a flowchart showing a process between a transmission process and a transmission destination process.

FIG. 8 is a diagram illustrating a processing example using a transmission process.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 CPU 20 Bus 30 Memory 40 Peripheral device 110, 130 Process 120 Shared memory 122 Communication content 210 Source process 212 Message to be transmitted 220 Transmission process 222 Message 230 Destination process 232 Message sent 242, 244, 246 Transmission process 310 Header part 340 Message body 410 Process for requesting brightness control (transmission source process) 420 Fade-out control process (transmission process) 430 Process for controlling screen brightness (transmission destination process)

Claims (5)

[Claims] 1. An inter-process communication system in a multi-process system in which a process is performed by a plurality of processes, a transmission means for starting a specific transmission process, passing a message by designating a destination process, and the activated transmission. In the process, a processing means for processing the passed message, a transmission process check means for checking the transmission process to see if there is a message addressed to itself, and a reception for receiving a message when there is a message addressed to itself And an inter-process communication system. 2. The inter-process communication system according to claim 1, wherein the transmission process is started as a child process of a transmission source process, and operates as a child process of a transmission destination process after receiving a message. Interprocess communication system. 3. The inter-process communication system according to claim 1, wherein a current time of a designated transmission destination process is set when a message is passed to said transmission process. 4. An inter-process communication method in a multi-process system in which processing is performed by a plurality of processes, a step of activating a specific transmission process, passing a message by specifying a destination process, and the activated transmission process. , A step of processing the passed message, a step of checking the transmission process to check whether there is a message addressed to the user, and a step of receiving the message if there is a message addressed to the user. An inter-process communication method comprising: 5. A recording medium storing a program capable of constructing the inter-process communication system according to claim 1 for a computer system.