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#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
int main(argc, argv)
int argc;
char **argv;
{
int shmid, i, pid, n_read, n_write;
char *mem, **arg_r, **arg_w;
if (argc < 2) {
printf("usage: sync [number readers] [number writers]\n");
exit(1);
}
n_read = atoi(argv[1]);
n_write = atoi(argv[2]);
if ((shmid = shmget(52, 1<<14, IPC_CREAT | 0666)) == -1){
perror("shmget: shmget failed");
exit(1);
}
if ((mem = shmat(shmid, NULL, 0)) == (char *) -1) {
perror("shmat");
exit(1);
}
for (i = 0; i < 1<<14; i++) {
*(mem + i) = 0x30;
}
arg_r = malloc(sizeof(char*) * 2);
arg_w = malloc(sizeof(char*) * 2);
*(arg_r + 1) = NULL;
*(arg_w + 1) = NULL;
for (i = 0; i < n_read; i++){
sprintf(*arg_r, "%d", i);
if (pid = fork()) {
printf("starting reader %d...\n", i);
} else {
execvp("./reader", arg_r);
}
}
for (i = 0; i < n_write; i++) {
sprintf(*arg_w, "%d", i);
if (pid = fork()) {
printf("starting writer %d...\n", i);
} else {
execvp("./writer", arg_w);
}
}
}
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