unsafe

I have some concurrent code which has an intermittent failure and I've reduced the problem down to two cases which seem identical, but where one fails and the other doesn't. I've now spent way too much time trying to create a minimal, complete example that fails, but without success, so I'm just posting the lines that fail in case anyone can see an obvious problem. Object lock = new Object(); struct MyValueType { readonly public int i1, i2; }; class Node { public MyValueType x; public int y; public Node z; }; volatile Node[] m_rg = new Node[300]; unsafe void Foo() { Node[] temp; while (true) {

I've recently encountered a situation where I need to create a generic method to read a datatype out of a byte array. I've created the following class: public class DataStream { public int Offset { get; set; } public byte[] Data { get; set; } public T Read<T>() where T : struct { unsafe { int dataLen = Marshal.SizeOf( typeof( T ) ); IntPtr dataBlock = Marshal.AllocHGlobal( dataLen ); Marshal.Copy( Data, Offset, dataBlock, dataLen ); T type = *( ( T* )dataBlock.ToPointer() ); Marshal.FreeHGlobal( dataBlock ); Offset += dataLen; return type; } } } Now, de-allocation issues aside, this code doesn

This question is a duplicate of 1042830 , but MonoTouch-specific. Is there a way that's safer than allocating an IntPtr, drawing into it using CGBitmapContext and then reading bytes at the appropriate offset? I don't know if it's kosher to answer your own question, but: protected CGBitmapContext CreateARGBBitmapContext(CGImage inImage) { var pixelsWide = inImage.Width; var pixelsHigh = inImage.Height; var bitmapBytesPerRow = pixelsWide * 4; var bitmapByteCount = bitmapBytesPerRow * pixelsHigh; //Note implicit colorSpace.Dispose() using(var colorSpace = CGColorSpace.CreateDeviceRGB()) { /

Why do I get the following error? Unsafe code may only appear if compiling with /unsafe"? I work in C# and Visual Studio 2008 for programming on Windows CE. To use unsafe code blocks, the project has to be compiled with the /unsafe switch on. Open the properties for the project, go to the Build tab and check the Allow unsafe code checkbox. Manoj Attal Here is a screenshot: ََََََََ Probably because you're using unsafe code. Are you doing something with pointers or unmanaged assemblies somewhere? Search your code for unsafe blocks or statements. These are only valid is compiled with /unsafe .

Hi how i can use unsafe keyword in web based application for pointers? In windows application we have setting in properties section of project under build tag we can check allow unsafe code checkbox, but in web based application how to allow unsafe code or any other in replacement of unsafe code (Pointer) asp.net c# Thank you. If this is a web application you can simply go to the properties of the project and allow unsafe code as you would do in any standard class library. If it is a web site you could try putting the following in your web.config: <system.codedom> <compilers> <compiler

I'm trying to convert a Vec of u32 s to a Vec of u8 s, preferably in-place and without too much overhead. My current solution relies on unsafe code to re-construct the Vec . Is there a better way to do this, and what are the risks associated with my solution? use std::mem; use std::vec::Vec; fn main() { let mut vec32 = vec![1u32, 2]; let vec8; unsafe { let length = vec32.len() * 4; // size of u8 = 4 * size of u32 let capacity = vec32.capacity() * 4; // ^ let mutptr = vec32.as_mut_ptr() as *mut u8; mem::forget(vec32); // don't run the destructor for vec32 // construct new vec vec8 = Vec::from

I have a [u8; 16384] and a u16 . How would I "temporarily transmute" the array so I can set the two u8 s at once, the first to the least significant byte and the second to the most significant byte? sellibitze As DK suggests , you probably shouldn't really use unsafe code to reinterpret the memory... but you can if you want to. If you really want to go that route, you should be aware of a couple of gotchas: You could have an alignment problem. If you just take a &mut [u8] from somewhere and convert it to a &mut [u16] , it could refer to some memory region that is not properly aligned to be

Can I somehow get an array from std::ptr::read ? I'd like to do something close to: let mut v: Vec<u8> = ... let view = &some_struct as *const _ as *const u8; v.write(&std::ptr::read<[u8, ..30]>(view)); Which is not valid in this form (can't use the array signature). Vladimir Matveev If you want to obtain a slice from a raw pointer, use std::slice::from_raw_parts() : let slice = unsafe { std::slice::from_raw_parts(some_pointer, count_of_items) }; If you want to obtain a mutable slice from a raw pointer, use std::slice::from_raw_parts_mut() : let slice = unsafe { std::slice::from_raw_parts_mut