SQLite共享内存数据库

我试图为我的多线程应用程序创建共享内存数据库,但似乎不起作用。我用过:

sqlite3_open("file:memdb1?mode=memory&cache=shared", &self->readdb)

就像这里描述的: https://www.sqlite.org/inmemorydb.html 但是它只是创建了名为 file:memdb1?mode=memory&cache=shared 似乎只是普通的文件:

lapsio@linux-tiph > stat file:memdb1\?mode=memory\&cache=shared 
  File: 'file:memdb1?mode=memory&cache=shared'
  Size: 9216            Blocks: 24         IO Block: 4096   regular file
Device: 2fh/47d Inode: 109010      Links: 1
Access: (0644/-rw-r--r--)  Uid: ( 1000/  lapsio)   Gid: (  100/   users)
Access: 2018-06-24 13:46:48.435300970 +0200
Modify: 2018-06-24 13:47:07.139406989 +0200
Change: 2018-06-24 13:47:07.139406989 +0200
 Birth: -

我的sqlite版本是

sqlite3 --version
3.8.10.2 2015-05-20 18:17:19 2ef4f3a5b1d1d0c4338f8243d40a2452cc1f7fe4