Untitled

/* program for file locking and releasing*/
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
int main() {
struct flock fl;
int fd;
fl.l_type = F_WRLCK; /* read/write lock */
fl.l_whence = SEEK_SET; /* beginning of file */
fl.l_start = 0; /* offset from l_whence */
fl.l_len = 0; /* length, 0 = to EOF */
fl.l_pid = getpid(); /* PID */
fd = open("locked_file", O_RDWR | O_EXCL); /* not 100% sure if O_EXCL
needed */
fcntl(fd, F_SETLKW, &fl); /* set lock */
usleep(10000000);
printf("\n release lock \n");
fl.l_type = F_UNLCK;
fcntl(fd, F_SETLK, &fl); /* unset lock */
}