Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>What are you trying to do exactly? Locals are on stack and arguments are too depending on the calling convention. Storing or returning the address of a local or argument is not good because it will get overriden. There is no way to prevent them from being overriden besides like not calling methods.</p> <p>If you turn on unmanaged debugging you can use the memory debugger and register window to see what is going on. </p> <p>Here is simpler to understand C example. Why does print not display the correct value. Because when the print function gets invoked its stack frame overwrites the value.</p> <pre><code>int* bad(int x, int y) { int sum = x + y; return &amp;sum; }; int* bad2(int x, int y) { x += y; return &amp;x; } int _tmain(int argc, _TCHAR* argv[]) { int* sum1 = bad(10, 10); int* sum2 = bad(100, 100); printf("%d bad", *sum1); // prints 200 instead of 20 sum1 = bad2(10, 10); sum2 = bad2(100, 100); printf("%d bad", *sum1); // prints 200 instead of 20 return 0; }; </code></pre> <p>Cant get the clr to hold on for it longer. One thing you can do is get the variable on the stack pushed further out. Below is an example. This is all bad though :(</p> <pre><code>using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Linq.Expressions; using System.Xml.Linq; using System.Runtime.InteropServices; namespace Bad { class Program { static void Main(string[] args) { Action a = () =&gt; Console.WriteLine("test"); Horror h = new Horror(); h.Fix(new Big(), ref a, new Big()); h.Clear(); Console.WriteLine(); } } [StructLayout(LayoutKind.Sequential, Size = 4096)] struct Big { } unsafe class Horror { void* _ptr; static void Handler() { Console.WriteLine("Hello world."); } public void Fix(Big big, ref Action action, Big big2) { action += Handler; var tr = __makeref(action); _ptr = (void*)&amp;tr; } public void Clear() { var tr = *(TypedReference*)_ptr; __refvalue(tr, Action) -= Handler; } } } </code></pre>
    singulars
    1. This table or related slice is empty.
    1. POKeep a TypedReference alive out of method block without returning it
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USAbdElRaheim
    1. USAbdElRaheim
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POKeep a TypedReference alive out of method block without returning it
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTAcceptedByOriginator
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTBountyClose
    1. COAbout why a pointer to a variable allocated on the stack may will be invalid after the call where it's pushed terminates, thanks for your explanation but that was the actual point I've used to ask the question -- Finding a way to allocate it on the heap. The method you suggested, though, is new to me and it works (even if as you said, it's really "evil"). Would you explain its trick? I will accept the answer in case better methods aren't provided. By "better" I mean a systematic way to push a `TypedReference` on the heap and retrieve it when needed.
      singulars
      1. PO
      1. USMir
    2. COsorry tr is actually a local that is getting created on the stack not an argument. You can use the static ToObject method and store the object as a field in your class. Still confused on purpose though? TypeReferences are mainly for __arglist and hacky stuff like this here http://stackoverflow.com/questions/4764573/why-is-typedreference-behind-the-scenes-its-so-fast-and-safe-almost-magical
      singulars
      1. PO
      1. USAbdElRaheim
    3. COThe purpose is finding out if there's a way to bypass the compiler's checks against persisting a `TypedReference` instance. `ToObject` lets me store it as an `object`, but I don't know how to unbox it.
      singulars
      1. PO
      1. USMir
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload