Chapter 14. Interprocess Communication

	Example	Relevant Functions
14.1	Send data from parent to child via a pipe	pipe, fork, close, write, read
14.2	Display a file by piping into a PAGER program (like more)	fopen, pipe, fork, close, fgets, strlen, write, ferror, waitpid, dup2, getenv, strrchr, execl
14.3	Routines to let a parent and child synchronize: (Similar to Sec. 10.17 but using pipes instead of signals) TELL_WAIT Init function TELL_PARENT Child: notify parent TELL_CHILD Parent: notify child WAIT_PARENT Child: wait for parent notification WAIT_CHILD Parent: wait for child notification	pipe, write, read
14.4	Display a file by piping into a PAGER program (Like 14.2 but using popen)	fopen, fgets, fputs, ferror, popen, pclose
14.5	Possible implementation of popen and pclose	popen : open_max (Stevens' library), calloc, pipe, fork, close, dup2, execl _exit, fdopen pclose : fileno, fclose, waitpid
14.6	filter (stdin->stdout) to convert uppercase to lowercase	getchar, putchar, isupper, tolower, fflush
14.7	Invoke UC->LC filter above to read commands Using popen in read mode	popen, fgets, fputs, fflush, pclose, putchar, err_sys (Stevens' library)
14.8	add2: filter (stdin->stdout) example: Read two numbers from stdin, write sum to stdout.	read, sscanf, sprintf, strlen, write, exit, err_sys (Stevens' library)
14.9	Test driver for 14.8 filter Catching SIGPIPE and acting appropriately.	signal, pipe, fork, close, fgets, strlen, write, read, fputs, ferror, dup2, execl, err_sys (Stevens' library)
14.10	add2: filter to add two numbers (like 14.8) Bad example: wrongly using buffered I/O (stdio). It needs: setvbuf(stdout, NULL, _IOLBF, 0) before the loop to work correctly.	sscanf, printf, fgets, err_sys (Stevens' library)
14.11	Shared memory example: Print where different types of data (static array, stack, heap, shared-mem) are stored.	printf, malloc, shmget, shmat, shmctl, err_sys (Stevens' library)
14.12	IPC between parent & child Using memory mapped I/O of /dev/zero. /dev/zero is used to get a mapped shared memory area initialized to 0. that parent & child can modify in turn.	open, mmap, close, fork, exit, TELL_WAIT, TELL_PARENT, TELL_CHILD, WAIT_PARENT, WAIT_CHILD, err_sys, err_quit (Stevens' lib)