--- /dev/null
+struct flock {
+ short int l_type; /* Type of lock: F_RDLCK, F_WRLCK, or F_UNLCK. */
+ short int l_whence; /* Where `l_start' is relative to (like `lseek').*/
+ off_t l_start; /* Offset where the lock begins. */
+ off_t l_len; /* Size of the locked area; zero means until EOF.*/
+ pid_t l_pid; /* Process holding the lock. */
+};