Linux和OS X上的Sqlite数据文件不兼容? [英] Sqlite data file on Linux and OS X incompatible?

问题描述

我创建一个表并通过在ARM Linux机器上执行以下命令来填充它

I create a table and fill it by executing the following on an ARM Linux machine

~ # sqlite3 /mnt/mmc/test.db
SQLite version 3.6.12
sqlite> create table a (d);
sqlite> insert into a values (1.5);
sqlite> select * from a;
1.5

然后我将文件传输到Mac并执行以下操作

I then transfer the file to my Mac and execute the following

themac:~ me$ sqlite3 test.db 
SQLite version 3.6.12
sqlite> select * from a;
5.30239915051991e-315

哇?我以为数据文件是平台无关的.

Whaaat? I thought the data file was platform independent.

推荐答案

我对SQLite并不了解，但这表明存在一个问题，其中两个64位IEEE 754格式double的32位字是如本例所示(在x86机器上使用gcc运行)，交换过来了:

I have no particular knowledge of SQLite, but this is indicative of a problem where two 32-bit words of a 64-bit IEEE 754 format double are swapped over, as you can see in this example (which was run using gcc on an x86 machine):

$ cat test.c
#include <stdio.h>

int main(void)
{
    union {
        double d;
        unsigned long long ull;
    } u;

    u.d = 1.5;
    printf("%016llx\n", u.ull);

    u.d = 5.30239915051991e-315;
    printf("%016llx\n", u.ull);

    return 0;
}

$ gcc -Wall -o test test.c
$ ./test
3ff8000000000000
000000003ff80000
$ 

这篇关于Linux和OS X上的Sqlite数据文件不兼容?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！