It *could* be every type ... It happens it is pretty similar, I admit I did make a table like you did.
Array.Copy seems to be as fast as Buffer.BlockCopy, but if anyone on this list has a different experience, please let me know. I know sizeof(T) could not work and I was writing that only to express what I was trying to do, but surely there is a clean way to get the size of T dynamically besides doing it by hand with a table ? Sébastien On 4/17/08, Curt Hagenlocher <[EMAIL PROTECTED]> wrote: > On Wed, Apr 16, 2008 at 10:10 PM, Sébastien Lorion > > <[EMAIL PROTECTED]> wrote: > > On 4/17/08, Curt Hagenlocher <[EMAIL PROTECTED]> wrote: > > > On Wed, Apr 16, 2008 at 8:31 PM, Sébastien Lorion > > > > > > <[EMAIL PROTECTED]> wrote: > > > > > > > I want the managed size, so Marshal.SizeOf does not return the correct > value. > > > > For example, sizeof(char) returns 2 and Marshal.SizeOf(typeof(char)) > returns 1. > > > > > > Huh. So it does. Are there any other types for which this is true? > > > > Well, basically every types ... Marshal.SizeOf returns the size of the > > equivalent unmanaged type. Another example would be boolean: Marshal > > returns 4 instead of 1. > > > As per the table below, "every type" may be a bit of an exaggeration > :). Of course, even one exception makes the technique useless. If > you're calling it often enough so that there really is a significant > perf gain to be had by using Buffer.BlockCopy over Array.Copy, why not > create a Dictionary<Type, int> and populate it with all the values you > expect to encounter? > > type marshal sizeof > char 1 2 > bool 4 1 > byte 1 1 > sbyte 1 1 > int16 2 2 > uint16 2 2 > int32 4 4 > uint32 4 4 > int64 8 8 > uint64 8 8 > float 4 4 > double 8 8 > decimal 16 16 > IntPtr 4 4 (on a 32-bit OS, uses IntPtr.Size instead of sizeof) > IntPtr 8 8 (on a 64-bit OS, uses IntPtr.Size instead of sizeof) > > > > I wanted to use Buffer.BlockCopy in a class with generic parameters > > and I could not use sizeof(T). > > > Which makes sense, because "sizeof" is a compile-time operator while > template instantiation happens at run time. > > > -- > > Curt Hagenlocher > [EMAIL PROTECTED] > > > =================================== > This list is hosted by DevelopMentor(R) http://www.develop.com > > View archives and manage your subscription(s) at http://discuss.develop.com > -- Sébastien www.sebastienlorion.com =================================== This list is hosted by DevelopMentor® http://www.develop.com View archives and manage your subscription(s) at http://discuss.develop.com
