dev/c/ParallelsTest/4npipe.c

68 lines
1.5 KiB
C

#include <stdlib.h>
#include <stdio.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <string.h>
#include <fcntl.h>
void syserr( const char *msg ) {
perror(msg);
exit(EXIT_FAILURE);
}
main()
{
int rfd, wfd;
char buff[64096];
int nb;
int ed;
remove("duck");
if( mkfifo( "duck", 0666 ) == -1 ) {
syserr( "mkfifo" );
}
switch( fork() ) {
case -1: syserr("fork" ); break;
case 0: // child
printf( "Child awakes\n" );
if( (rfd = open( "duck", O_RDWR )) == -1 ) {
syserr( "open for reading" );
}
printf("Child: open completes\n");
for( ; ; ) {
if( (nb = read( rfd, buff, 200 )) == -1 ) {
syserr( "read" );
}
if( nb == 0 ) {
printf("No more data\n");
printf("child terminates 0\n");
exit( 0 );
}
buff[nb] = '\0';
printf("nb = %d Buff = |%s|\n", nb, buff);
}
break;
default: // parent
printf( "Parent awake\n" );
if( (wfd = open( "duck", O_RDWR )) == -1 ) {
syserr( "open for writing" );
}
printf("Parent opened pipe to write\n");
for( ed = 0; ed < 4; ed++ ) {
sprintf( buff, "duckie %d", ed + 1 );
if(write( wfd, buff, strlen(buff)) != strlen(buff)) {
syserr( "write" );
}
}
printf("parent terminates\n");
close(wfd);
remove("duck");
sleep(1);
}
}