以下常量由此扩展定义，只有在将扩展编译到PHP中或在运行时动态加载时才可用。
F_DUPFD (int)
F_GETFD (int)
F_GETFL (int)
F_GETLK (int)
F_GETOWN (int)
F_RDLCK (int)
F_SETFL (int)
F_SETLK (int)
F_SETLKW (int)
F_SETOWN (int)
F_UNLCK (int)
F_WRLCK (int)
O_APPEND (int)
O_ASYNC (int)
O_CREAT (int)
O_EXCL (int)
O_NDELAY (int)
O_NOCTTY (int)
O_NONBLOCK (int)
O_RDONLY (int)
O_RDWR (int)
O_SYNC (int)
O_TRUNC (int)
O_WRONLY (int)
S_IRGRP (int)
S_IROTH (int)
S_IRUSR (int)
S_IRWXG (int)
S_IRWXO (int)
S_IRWXU (int)
S_IWGRP (int)
S_IWOTH (int)
S_IWUSR (int)
S_IXGRP (int)
S_IXOTH (int)
S_IXUSR (int)