Re: [libvirt] virDomainInfo marshalling prolem

On Fri, Oct 29, 2010 at 04:19:22PM +0200, Matthias Bolte wrote: > 2010/10/29  &lt;arnaud.champion(a)devatom.fr&gt;: > > Hi, > > > > I am working on the marshaling of the virDomainInfo structure. I have > > marshalled it in this way : > > > > > > /// > > > > <summary> > > > > /// Structure to handle domain informations > > > > /// </summary> > > > > [ > > > > StructLayout(LayoutKind.Sequential)] > > > > public class DomainInfo > > > > { > > > >     /// <summary> > >     /// The running state, one of virDomainState. > >     /// </summary> > >     private Byte state; > >     /// <summary> > >     /// The maximum memory in KBytes allowed. > >     /// </summary> > >     public int maxMem; > >     /// <summary> > >     /// The memory in KBytes used by the domain. > >     /// </summary> > >     public int memory; > >     /// <summary> > >     /// The number of virtual CPUs for the domain. > >     /// </summary> > >     public short nrVirtCpu; > >     /// <summary> > >     /// The CPU time used in nanoseconds. > >     /// </summary> > >     public long cpuTime; > >     /// <summary> > >     /// The running state, one of virDomainState. > >     /// </summary> > >     public DomainState State { get { return (DomainState)state; } } > > > > } > > > > It work fine in 32 bits, but not in 64 bits, it seems that packing in 64 > > bits is different so infos are not in order. Am I right ? > > > > In the struct looks like this > > struct _virDomainInfo { >     unsigned char state;        /* the running state, one of virDomainState */ >     unsigned long maxMem;       /* the maximum memory in KBytes allowed */ >     unsigned long memory;       /* the memory in KBytes used by the domain */ >     unsigned short nrVirtCpu;   /* the number of virtual CPUs for the domain */ >     unsigned long long cpuTime; /* the CPU time used in nanoseconds */ > }; > > but you mapped unsigned long to int. First of all you should map this > to an unsigned type. You also lost the unsigned for some other > members. > > The problem probably is that long in C is 32bit on a 32bit platform an > 64bit on a 64bit platform. You mapped it to int that is always 32bit > in C#, when I looked it up correctly. Not quite. Windows just had to do things diffrently on 64-bit and so used the LLP64 model instead of LP64 used by the rest of the world :-(  http://technet.microsoft.com/en-us/library/bb496995.aspx  In the UNIX/64 data model:      The size of int is 32 bits and the size of long and pointers is 64 bits.  In the Win64 model:      The size of int and long is 32 bits; the size of int64 (new type) and pointers is 64 bits. Regards, Daniel