Re: [libvirt] virDomainInfo marshalling prolem

2010/10/29 Daniel P. Berrange <berrange(a)redhat.com&gt;: > On Fri, Oct 29, 2010 at 04:19:22PM +0200, Matthias Bolte wrote: >> 2010/10/29 <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 > Ah yes. I forgot about that one. So this gets even more complicated when you want to get the C# bindings working on 32 and 64 bit Windows and Linux. Matthias