字节序的判断

/*
** For internal use
*/
static bool g_bCheckByteOrder = false;
static bool g_bBigEndian = false;
bool isBigEndian()
{
    if(g_bCheckByteOrder)
    return g_bBigEndian;

    union{
    short inum;
    char  c[sizeof(short)];
    }un;
    un.inum = 0x0102;

    /* check the byte order */
    if(un.c[0] == 1 && un.c[1] == 2)
    {
    //g_bBigEndian = false;
    g_bBigEndian = true;
    }
    else if(un.c[0] == 2 && un.c[1] == 1)
    {
    //g_bBigEndian = true;
    g_bBigEndian = false;
    }
   
    g_bCheckByteOrder = true;
    return g_bBigEndian;
}