Bug in TC2-d2 pipe()

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        Bug report from : Michael Kerrisk , self

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@ page 1 line 27866  section pipe() comment {pipe example}

Problem:

This is an EXAMPLE for the waitpid() man page.  Line number 
references are to TC1.


Action:

Change

"None"

to the following:

[[
The following example demonstrates the use of a pipe to 
transfer data between a parent process and a child process.  
Error handling is excluded, but otherwise this code 
demonstrates good practice when using pipes: after the fork() 
the two processes close the unused ends of the pipe before 
they commence transferring data.


int fildes[2];
const int BSIZE = 100;
char buf[BSIZE];
ssize_t nbytes;

pipe(fildes);

switch (fork()) {
case -1: /* Handle error */
    break;

case 0:     /* Child  - reads from pipe */
    close(fildes[1]);                       /* Write end is unused */
    nbytes = read(fildes[0], buf, BSIZE);   /* Get data from pipe */
    /* At this point, a further read would see end of file... */
    close(fildes[0]);                       /* Finished with pipe */
    exit(EXIT_SUCCESS);

default:    /* Parent - writes to pipe */
    close(fildes[0]);                       /* Read end is unused */
    write(fildes[1], "Hello world\n", 12);  /* Write data on pipe */
    close(fildes[1]);                       /* Child will see EOF */
    exit(EXIT_SUCCESS);
}
]]