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/**
* un programma, lanciato due volte come trasmittente e ricevente,
* comunica tramite una pipe con nome sul file-system (FIFO);
*
* da invocare come:
* - trasmittente: fifo T
* - ricevente: fifo R
*
* si scambiano messaggi di dimensione fissa
*/
#include
#include
#include
#include
#include
#include
#include
#define BUFSIZE 1024
#define NUM_MSG 20
int main(int argc, char *argv[]) {
int i, fd, len;
char buffer[BUFSIZE];
const char *pathname = "/tmp/fifo";
const char *static_message = "Hello!";
if (argc < 2) {
fprintf(stderr, "uso: %s T|R\n", argv[0]);
exit(1);
}
if (argv[1][0] == 'T') { // trasmittente
if (mkfifo(pathname, 0700) == -1) {
perror(pathname);
// exit(1);
}
if ((fd = open(pathname, O_WRONLY)) == -1) {
perror(pathname);
unlink(pathname);
exit(1);
}
for (i = 0; i < NUM_MSG; i++) {
write(fd, static_message, strlen(static_message) + 1);
printf("messaggio n.%d inviato: '%s'\n", i, static_message);
}
exit(0);
} else if (argv[1][0] == 'R') { // ricevente
if ((fd = open(pathname, O_RDONLY)) == -1) {
perror(pathname);
unlink(pathname);
exit(1);
}
for (i = 0; i < NUM_MSG; i++) {
len = read(fd, buffer, strlen(static_message) + 1);
// notare la specifica dell'esatta dimensione attesa del messaggio
printf("messaggio ricevuto (%d byte): %s\n", len, buffer);
}
unlink(pathname);
exit(0);
} else {
fprintf(stderr, "parametro non atteso!\n");
unlink(pathname);
exit(1);
}
}