| 1 | #include <unistd.h> |
| 2 | #include <fcntl.h> |
| 3 | #include <sys/wait.h> |
| 4 | |
| 5 | int main() { |
| 6 | int i, fd = 1; |
| 7 | |
| 8 | if (fork()) //il s'agit du père |
| 9 | { |
| 10 | lseek(fd, 0, 0); |
| 11 | if (lockf(fd, F_LOCK, 1) < 0) { |
| 12 | write(fd, "pere lockf failed\n", 18); |
| 13 | return -1; |
| 14 | } |
| 15 | for (i = 0; i < 5; i++) { |
| 16 | write(fd, "pere ecrit\n", 12); |
| 17 | sleep(1); |
| 18 | } |
| 19 | write(fd, "pere va liberer le verrou\n", 26); |
| 20 | lseek(fd, 0, 0); |
| 21 | lockf(fd, F_ULOCK, 0); |
| 22 | wait(NULL); |
| 23 | } else { //il s'agit du fils |
| 24 | lseek(fd, 0, 0); //verrouillé l'octet 0 |
| 25 | if (lockf(fd, F_LOCK, 1) < 0) { |
| 26 | write(fd, "fils lockf failed\n", 18); |
| 27 | return -1; |
| 28 | } |
| 29 | for (i = 0; i < 4; i++) { |
| 30 | write(fd, "fils ecrit\n", 12); |
| 31 | sleep(1); |
| 32 | } |
| 33 | write(fd, "fils va liberer le verrou\n", 26); |
| 34 | lseek(fd, 0, 0); |
| 35 | lockf(fd, F_ULOCK, 0); |
| 36 | } |
| 37 | close(fd); |
| 38 | return 0; |
| 39 | } |