University:
California State University, Northridge
Course:
COMP 222 | Computer Organization
Academic year:

2024
Views:

186

Pages:

11
Author:

Vivian Bernard

Chapter 11 Interprocess Communication 1 IPC ALTERNATIVES Byte- and message-oriented Windows objects   Pipes (anonymous and named) Mailslots (subject of this chapter) Networking   Windows sockets (standard interface to TCP/IP) Remote Procedure Calls (RPCs) Object-oriented  OLE; COM (Component Object Model) Some others   Shared memory with memory-mapped files Files 3 OVERVIEW (1 of 2) Interprocess Communication (IPC) is provided with byteand message-based “pipes” Anonymous pipes   Well suited for redirecting the output of one program to the input of another Anonymous pipes are stream oriented 4 OVERVIEW (2 of 2) Named pipes      Allow networked communication Multiple handles on the same pipe Transaction-oriented named pipe functions Ideal for creating simple client/server systems Named pipes are message oriented Mailslots allow for one-to-many message broadcasting 5 TOPIC I Anonymous Pipes 7 ANONYMOUS PIPES     Allow for one-way (half-duplex), character-based IPC Two handles: a read handle and a write handle Specify the suggested buffer size for the pipe Usually you want the pipes to be inheritable 8 IPC USING AN ANONYMOUS PIPE pipe CreatePipe (&hRead, &hWrite) StartUp.hStdOutput = hWrite CreateProcess ("Program1") StartUp.hStdInput = hRead CreateProcess ("Program2") WaitForMultipleObjects Program1 hIn = CreateFile (argv [1]) while ( ) { ReadFile (hIn) WriteFile (hWrite) } ExitProcess (0) Program2 Pipe hOut = CreateFile (argv [2]) while ( ) { ReadFile (hRead) } WriteFile (hOut) 9 ANONYMOUS PIPE MANAGEMENT (1 of 2) BOOL CreatePipe (PHANDLE phRead, PHANDLE phWrite, LPSECURITY_ATTRIBUTES lpsa, DWORD cbPipe) 10 ANONYMOUS PIPE MANAGEMENT (2 of 2) cbPipe The pipe byte size; use zero to get the default value phRead  Address of a HANDLE  CreatePipe will set *phRead  phWrite is used for the write handle to the new pipe  Reading blocks if pipe is empty; otherwise read will accept as many bytes as are in the pipe, up to the number specified in the ReadFile call Writing to a full pipe will block 11 LAB 6–A (1 of 2) We now have a collection of command line utilities, including cat, ls (with options for file size and security), grep, and sort (several versions)    Write a program, pipe, which will take two commands and connect them with anonymous pipes (assigned to standard input and output) Use the = sign to separate the two program names Use the model in the anonymous pipe figure. The original input is standard input and the results are to go to standard output. 12 LAB 6–A (2 of 2) Command form: pipe Program1 = Program2 An additional utility, the wc word count program, is included with the solutions  It is useful in the role of Program2 13