Операционные системы. Теория и практика. Замятин А.В. - 276 стр.

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#include <unistd.h>

#include <sys/ipc.h>

#include <sys/msg.h>

#include <stdlib.h>

#define MSG_R (S_IRUSR | S_IRGRP | S_IROTH)

#define MAXMSG (8192 + sizeof(long))

int main(int argc, char **argv)

{

int c, flag, mqid;

long type;

ssize_t n;

struct msgbuf *buff;

type = flag = 0;

while ( (c = getopt(argc, argv, "nt:")) != -1) {

switch (c) {

case 'n':

flag |= IPC_NOWAIT;

break;

case 't':

type = atol(optarg);

break;

}

if (optind != argc - 1)

{

printf("usage: msgrcv [ -n ][ -t type ]<path_to_file>");

return 0;

}

mqid = msgget(ftok(argv[optind], 0), MSG_R);

buff = (msgbuf*) malloc(MAXMSG);

n = msgrcv(mqid, buff, MAXMSG, type, flag);

printf("read %d bytes, type = %ld\n", n, buff->mtype);

return 0;