Why can't I use Marshal.SizeOf() to calculate the size of an instance of type ValueTuple?
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0
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Why does the following code:
ValueTuple<double, double> origin = (0.0, 0.0);
Console.WriteLine($"Size of ValueTuple<double, double>: {Marshal.SizeOf(origin)}");
throw System.ArgumentException: 'Type
'System.ValueTuple`2[System.Double,System.Double]' cannot be marshaled
as an unmanaged structure; no meaningful size or offset can be computed.'
c# .net valuetuple
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0
down vote
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Why does the following code:
ValueTuple<double, double> origin = (0.0, 0.0);
Console.WriteLine($"Size of ValueTuple<double, double>: {Marshal.SizeOf(origin)}");
throw System.ArgumentException: 'Type
'System.ValueTuple`2[System.Double,System.Double]' cannot be marshaled
as an unmanaged structure; no meaningful size or offset can be computed.'
c# .net valuetuple
2
Sounds pretty definitive to me. what is the actual problem you are trying to solve
– TheGeneral
Nov 20 at 0:54
Unless you're actually planning to send something into the unmanaged world,Marshal.SizeOf
may as well be replaced withRandom.Next
. It tells you then size of the unmanaged representation of the type, which is only meaningful if you'll create such a thing, and as it says here, you can't create an unmanaged representation of a valuetuple.
– Damien_The_Unbeliever
Nov 20 at 7:10
I'm not attempting to marshal a ValueTuple to unmanaged code. However, the actual motivation is probably controversial. I have my own implementation of IList<T> called BigList<T> that uses a pool of buffers that are small enough to stay off the Large Object Heap. This requires knowing the size in bytes of T. I've been using Marshal.SizeOf() for this purpose.
– mikevg
Nov 20 at 16:00
1
To avoid LOH limit, you need managed size of T, not marshalled size of T returned byMarshall.SizeOf()
, which can be different (What’s the difference? sizeof and Marshal.SizeOf). Some workarounds here and here. Also remember that array size is not just size_of_T * array_length but array needs some additional memory (to store array length, dimension, object headers) which is also runtime-dependent.
– Ňuf
Nov 20 at 21:38
I knew that the "managed" and "unmanaged" sizes of T could be different but my situation is limited to simple value types T and my implementation is not particularly sensitive to errors using Marshal.SizeOf(). My buffers are actually arrays of T and I can tell if they end up on LOH. What I was missing is that I can Emit OpCodes.Sizeof to get the "managed" size. This fixes my problem and I can now create BigList<T> where T is a ValueTuple. Thanks!
– mikevg
Nov 21 at 1:14
add a comment |
up vote
0
down vote
favorite
up vote
0
down vote
favorite
Why does the following code:
ValueTuple<double, double> origin = (0.0, 0.0);
Console.WriteLine($"Size of ValueTuple<double, double>: {Marshal.SizeOf(origin)}");
throw System.ArgumentException: 'Type
'System.ValueTuple`2[System.Double,System.Double]' cannot be marshaled
as an unmanaged structure; no meaningful size or offset can be computed.'
c# .net valuetuple
Why does the following code:
ValueTuple<double, double> origin = (0.0, 0.0);
Console.WriteLine($"Size of ValueTuple<double, double>: {Marshal.SizeOf(origin)}");
throw System.ArgumentException: 'Type
'System.ValueTuple`2[System.Double,System.Double]' cannot be marshaled
as an unmanaged structure; no meaningful size or offset can be computed.'
c# .net valuetuple
c# .net valuetuple
edited Nov 20 at 0:55
![](https://i.stack.imgur.com/TbwHb.png?s=32&g=1)
![](https://i.stack.imgur.com/TbwHb.png?s=32&g=1)
TheGeneral
26.4k63163
26.4k63163
asked Nov 20 at 0:54
mikevg
234
234
2
Sounds pretty definitive to me. what is the actual problem you are trying to solve
– TheGeneral
Nov 20 at 0:54
Unless you're actually planning to send something into the unmanaged world,Marshal.SizeOf
may as well be replaced withRandom.Next
. It tells you then size of the unmanaged representation of the type, which is only meaningful if you'll create such a thing, and as it says here, you can't create an unmanaged representation of a valuetuple.
– Damien_The_Unbeliever
Nov 20 at 7:10
I'm not attempting to marshal a ValueTuple to unmanaged code. However, the actual motivation is probably controversial. I have my own implementation of IList<T> called BigList<T> that uses a pool of buffers that are small enough to stay off the Large Object Heap. This requires knowing the size in bytes of T. I've been using Marshal.SizeOf() for this purpose.
– mikevg
Nov 20 at 16:00
1
To avoid LOH limit, you need managed size of T, not marshalled size of T returned byMarshall.SizeOf()
, which can be different (What’s the difference? sizeof and Marshal.SizeOf). Some workarounds here and here. Also remember that array size is not just size_of_T * array_length but array needs some additional memory (to store array length, dimension, object headers) which is also runtime-dependent.
– Ňuf
Nov 20 at 21:38
I knew that the "managed" and "unmanaged" sizes of T could be different but my situation is limited to simple value types T and my implementation is not particularly sensitive to errors using Marshal.SizeOf(). My buffers are actually arrays of T and I can tell if they end up on LOH. What I was missing is that I can Emit OpCodes.Sizeof to get the "managed" size. This fixes my problem and I can now create BigList<T> where T is a ValueTuple. Thanks!
– mikevg
Nov 21 at 1:14
add a comment |
2
Sounds pretty definitive to me. what is the actual problem you are trying to solve
– TheGeneral
Nov 20 at 0:54
Unless you're actually planning to send something into the unmanaged world,Marshal.SizeOf
may as well be replaced withRandom.Next
. It tells you then size of the unmanaged representation of the type, which is only meaningful if you'll create such a thing, and as it says here, you can't create an unmanaged representation of a valuetuple.
– Damien_The_Unbeliever
Nov 20 at 7:10
I'm not attempting to marshal a ValueTuple to unmanaged code. However, the actual motivation is probably controversial. I have my own implementation of IList<T> called BigList<T> that uses a pool of buffers that are small enough to stay off the Large Object Heap. This requires knowing the size in bytes of T. I've been using Marshal.SizeOf() for this purpose.
– mikevg
Nov 20 at 16:00
1
To avoid LOH limit, you need managed size of T, not marshalled size of T returned byMarshall.SizeOf()
, which can be different (What’s the difference? sizeof and Marshal.SizeOf). Some workarounds here and here. Also remember that array size is not just size_of_T * array_length but array needs some additional memory (to store array length, dimension, object headers) which is also runtime-dependent.
– Ňuf
Nov 20 at 21:38
I knew that the "managed" and "unmanaged" sizes of T could be different but my situation is limited to simple value types T and my implementation is not particularly sensitive to errors using Marshal.SizeOf(). My buffers are actually arrays of T and I can tell if they end up on LOH. What I was missing is that I can Emit OpCodes.Sizeof to get the "managed" size. This fixes my problem and I can now create BigList<T> where T is a ValueTuple. Thanks!
– mikevg
Nov 21 at 1:14
2
2
Sounds pretty definitive to me. what is the actual problem you are trying to solve
– TheGeneral
Nov 20 at 0:54
Sounds pretty definitive to me. what is the actual problem you are trying to solve
– TheGeneral
Nov 20 at 0:54
Unless you're actually planning to send something into the unmanaged world,
Marshal.SizeOf
may as well be replaced with Random.Next
. It tells you then size of the unmanaged representation of the type, which is only meaningful if you'll create such a thing, and as it says here, you can't create an unmanaged representation of a valuetuple.– Damien_The_Unbeliever
Nov 20 at 7:10
Unless you're actually planning to send something into the unmanaged world,
Marshal.SizeOf
may as well be replaced with Random.Next
. It tells you then size of the unmanaged representation of the type, which is only meaningful if you'll create such a thing, and as it says here, you can't create an unmanaged representation of a valuetuple.– Damien_The_Unbeliever
Nov 20 at 7:10
I'm not attempting to marshal a ValueTuple to unmanaged code. However, the actual motivation is probably controversial. I have my own implementation of IList<T> called BigList<T> that uses a pool of buffers that are small enough to stay off the Large Object Heap. This requires knowing the size in bytes of T. I've been using Marshal.SizeOf() for this purpose.
– mikevg
Nov 20 at 16:00
I'm not attempting to marshal a ValueTuple to unmanaged code. However, the actual motivation is probably controversial. I have my own implementation of IList<T> called BigList<T> that uses a pool of buffers that are small enough to stay off the Large Object Heap. This requires knowing the size in bytes of T. I've been using Marshal.SizeOf() for this purpose.
– mikevg
Nov 20 at 16:00
1
1
To avoid LOH limit, you need managed size of T, not marshalled size of T returned by
Marshall.SizeOf()
, which can be different (What’s the difference? sizeof and Marshal.SizeOf). Some workarounds here and here. Also remember that array size is not just size_of_T * array_length but array needs some additional memory (to store array length, dimension, object headers) which is also runtime-dependent.– Ňuf
Nov 20 at 21:38
To avoid LOH limit, you need managed size of T, not marshalled size of T returned by
Marshall.SizeOf()
, which can be different (What’s the difference? sizeof and Marshal.SizeOf). Some workarounds here and here. Also remember that array size is not just size_of_T * array_length but array needs some additional memory (to store array length, dimension, object headers) which is also runtime-dependent.– Ňuf
Nov 20 at 21:38
I knew that the "managed" and "unmanaged" sizes of T could be different but my situation is limited to simple value types T and my implementation is not particularly sensitive to errors using Marshal.SizeOf(). My buffers are actually arrays of T and I can tell if they end up on LOH. What I was missing is that I can Emit OpCodes.Sizeof to get the "managed" size. This fixes my problem and I can now create BigList<T> where T is a ValueTuple. Thanks!
– mikevg
Nov 21 at 1:14
I knew that the "managed" and "unmanaged" sizes of T could be different but my situation is limited to simple value types T and my implementation is not particularly sensitive to errors using Marshal.SizeOf(). My buffers are actually arrays of T and I can tell if they end up on LOH. What I was missing is that I can Emit OpCodes.Sizeof to get the "managed" size. This fixes my problem and I can now create BigList<T> where T is a ValueTuple. Thanks!
– mikevg
Nov 21 at 1:14
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2
Sounds pretty definitive to me. what is the actual problem you are trying to solve
– TheGeneral
Nov 20 at 0:54
Unless you're actually planning to send something into the unmanaged world,
Marshal.SizeOf
may as well be replaced withRandom.Next
. It tells you then size of the unmanaged representation of the type, which is only meaningful if you'll create such a thing, and as it says here, you can't create an unmanaged representation of a valuetuple.– Damien_The_Unbeliever
Nov 20 at 7:10
I'm not attempting to marshal a ValueTuple to unmanaged code. However, the actual motivation is probably controversial. I have my own implementation of IList<T> called BigList<T> that uses a pool of buffers that are small enough to stay off the Large Object Heap. This requires knowing the size in bytes of T. I've been using Marshal.SizeOf() for this purpose.
– mikevg
Nov 20 at 16:00
1
To avoid LOH limit, you need managed size of T, not marshalled size of T returned by
Marshall.SizeOf()
, which can be different (What’s the difference? sizeof and Marshal.SizeOf). Some workarounds here and here. Also remember that array size is not just size_of_T * array_length but array needs some additional memory (to store array length, dimension, object headers) which is also runtime-dependent.– Ňuf
Nov 20 at 21:38
I knew that the "managed" and "unmanaged" sizes of T could be different but my situation is limited to simple value types T and my implementation is not particularly sensitive to errors using Marshal.SizeOf(). My buffers are actually arrays of T and I can tell if they end up on LOH. What I was missing is that I can Emit OpCodes.Sizeof to get the "managed" size. This fixes my problem and I can now create BigList<T> where T is a ValueTuple. Thanks!
– mikevg
Nov 21 at 1:14