1#include <sys/ipc.h> 2#include <sys/stat.h> 3 4key_t ftok(const char* path, int id) { 5 struct stat st; 6 if (stat(path, &st) < 0) 7 return -1; 8 9 return ((st.st_ino & 0xffff) | ((st.st_dev & 0xff) << 16) | ((id & 0xff) << 24)); 10} 11