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  • Threads are blocked in malloc and free, virtual size

    - by Albert Wang
    Hi, I'm running a 64-bit multi-threaded program on the windows server 2003 server (X64), It run into a case that some of the threads seem to be blocked in the malloc or free function forever. The stack trace is like follows: ntdll.dll!NtWaitForSingleObject() + 0xa bytes ntdll.dll!RtlpWaitOnCriticalSection() - 0x1aa bytes ntdll.dll!RtlEnterCriticalSection() + 0xb040 bytes ntdll.dll!RtlpDebugPageHeapAllocate() + 0x2f6 bytes ntdll.dll!RtlDebugAllocateHeap() + 0x40 bytes ntdll.dll!RtlAllocateHeapSlowly() + 0x5e898 bytes ntdll.dll!RtlAllocateHeap() - 0x1711a bytes MyProg.exe!malloc(unsigned __int64 size=0) Line 168 C MyProg.exe!operator new(unsigned __int64 size=1) Line 59 + 0x5 bytes C++ ntdll.dll!NtWaitForSingleObject() ntdll.dll!RtlpWaitOnCriticalSection() ntdll.dll!RtlEnterCriticalSection() ntdll.dll!RtlpDebugPageHeapFree() ntdll.dll!RtlDebugFreeHeap() ntdll.dll!RtlFreeHeapSlowly() ntdll.dll!RtlFreeHeap() MyProg.exe!free(void * pBlock=0x000000007e8e4fe0) C BTW, the param values passed to the new operator is not correct here maybe due to optimization. Also, at the same time, I found in the process Explorer, the virtual size of this program is 10GB, but the private bytes and working set is very small (<2GB). We did have some threads using virtualalloc but in a way that commit the memory in the call, and these threads are not blocked. m_pBuf = VirtualAlloc(NULL, m_size, MEM_COMMIT, PAGE_READWRITE); ...... VirtualFree(m_pBuf, 0, MEM_RELEASE); This looks strange to me, seems a lot of virtual space is reserved but not committed, and malloc/free is blocked by lock. I'm guessing if there's any corruptions in the memory/object, so plan to turn on gflag with pageheap to troubleshoot this. Does anyone has similar experience on this before? Could you share with me so I may get more hints? Thanks a lot!

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  • wpf progress bar slows 10x times serial port communications... how could be possible that?

    - by D_Guidi
    I know that this could look a dumb question, but here's my problem. I have a worker dialog that "hides" a backgroundworker, so in a worker thread I do my job, I report the progress in a standard way and then I show the results in my WPF program. The dialog contains a simply animated gif and a standard wpf progress bar, and when a progress is notified I set Value property. All lokks as usual and works well for any kind of job, like web service calls, db queries, background elaboration and so on. For my job we use also many "couplers", card readers that reads data from smart card, that are managed with native C code that access to serial port (so, I don't use .NET SerialPort object). I have some nunit tests and I read a sample card in 10 seconds, but using my actual program, under the backgroundworker and showing my worker dialog, I need 1.30 minutes to do the SAME job. I struggled into problem for days until I decide to remove the worker dialog, and without dialog I obtain the same performances of the tests! So I investigated, and It's not the dialog, not the animated gif, but the wpf progress bar! Simply the fact that a progress bar is shown (so, no animation, no Value set called, nothing of nothing) slows serialport communicatitons. Looks incredible? I've tested this behavior and it's exactly what happens.

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  • SQL query: Last but one rank for user

    - by Derk
    My table structure looks like this: create table rankings ( id IDENTITY NOT NULL, user_id INT NOT NULL, game_poule_id INT NOT NULL, rank INT NOT NULL, insertDate DATETIME NOT NULL, FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE, FOREIGN KEY (game_poule_id) REFERENCES game_poules(id) ON DELETE CASCADE ); All old rankings of users per game are saved in this table. Now I want to have the last but one rank in the table for all users in a gamepoule. Has someone an idea how to achive this? Thanks

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  • Variable modification in a child process

    - by teaLeef
    I am working on Bryant and O'Hallaron's Computer Systems, A Programmer's Perspective. Exercise 8.16 asks for the output of a program like (I changed it because they use a header file you can download on their website): #include <stdio.h> #include <stdlib.h> #include <sys/types.h> #include <sys/wait.h> #include <errno.h> #include <unistd.h> #include <string.h> int counter = 1; int main() { if (fork() == 0){ counter--; exit(0); } else{ Wait(NULL); printf("counter = %d\n", ++counter); } exit(0); } I answered "counter = 1" because the parent process waits for its children to terminate and then increments counter. But the child first decrements it. However, when I tested the program, I found that the correct answer was "counter = 2". Is the variable "counter" different in the child and in the parent process? If not, then why is the answer 2?

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  • Mercurial Subrepos, how to control which changeset I want to use for a subrepo?

    - by Lasse V. Karlsen
    I am reading up on subrepos, and have been running some tests locally, seems to work OK so far, but I have one question. How do I specify/control which changeset I want to use for a particular subrepo? For instance, let's say I have the following two projects: class library application o fourth commit o second commit, added a feature | | o third commit o initial commit | | o second commit |/ o initial commit Now, I want the class library as a subrepo of my application, but due to the immaturity of the longest branch (the one ending up as fourth commit), I want to temporarily use the "second commit" tip. How do I go about configuring that, assuming it is even possible? Here's a batch file that sets up the above two repos + adds the library as a subrepo. If you run the batch file, it will output: [C:\Temp] :test ... v4 As you can see from that last line there, it verifies the contents of the file in the class library, which is "v4" from the fourth commit. I'd like it to be "v2", and persist as "v2" until I'm ready to pull down a newer version from the class library repository. Can anyone tell me if it is possible to do what I want, and if so, what I need to do in order to lock my subrepo to the right changeset? Batch-file: @echo off if exist app rd /s /q app if exist lib rd /s /q lib if exist app-clone rd /s /q app-clone rem == app == hg init app cd app echo program>main.txt hg add main.txt hg commit -m "initial commit" echo program+feature1>main.txt hg commit -m "second commit, added a feature" cd .. rem == lib == hg init lib cd lib echo v1>lib.txt hg add lib.txt hg commit -m "initial commit" echo v2>lib.txt hg commit -m "second commit" hg update 0 echo v3>lib.txt hg commit -m "third commit" echo v4>lib.txt hg commit -m "fourth commit" cd .. rem == subrepos == cd app hg clone ..\lib lib echo lib = ..\lib >.hgsub hg add .hgsub hg commit -m "added subrepo" cd .. rem == clone == hg clone app app-clone type app-clone\lib\lib.txt

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  • Is JSON array parsable?

    - by Alex
    I have a YQL query that extracts data from a page and returns it to my script as JSON. The JSON is huge, and as such, here's my question: Is JSON array parsable? So that I can iterate over the entire JSON structure?

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  • Decimal To Octal Converter, last digit issue

    - by Srishan Supertramp
    I tried making a C program to convert a user entered decimal number to octal. I wrote the C code with my own logic without any research of how other users try to do it. It works fine for the number 601 and some other numbers but for most numbers it returns the octal equivalent with the last digit being 1 less than it should be. For 75 it returns 112 instead of 113. I realize using printf with %o gets the job done but it's kind of defeating the purpose of learning to program. Here's my code: #include <stdio.h> #include <math.h> /* converting decimal to octal */ int main() { int n,x,y,p,s; printf("Enter a decimal number "); scanf("%d",&x); s=0;p=0; while (x!=0) { y=x%8; s=s+y*pow(10,p); x=(x-y)/8; p=p+1; } printf("the octal equivalent is: %d\n",s); getch(); return 0; }

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  • Write a SQL to meet my requirement.

    - by rgksugan
    I have been trying to solve this problem for a lot of days. But wouldn't. Please help me. I need a SQL to list product_code, product_name, qty_sold, last_order_date for all the products that have been sold within a date range sorted by the number of quantity sold. My Table structure: tbl_product(product_id,product_code,product_name) tbl_order_detail(order_item_id,order_id,product_id,quantity) tbl_order(order_id,order_date)

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  • F# - POCO Class

    - by ebb
    Hey there! I'm trying to write a POCO class in proper F#... But something is wrong.. The C# code that I want to "translate" to proper F# is: public class MyTest { [Key] public int ID { get; set; } public string Name { get; set; } } The closest I can come to the above code in F# is something like: type Mytest() = let mutable _id : int = 0; let mutable _name : string = null; [<KeyAttribute>] member x.ID with public get() : int = _id and public set(value) = _id <- value member x.Name with public get() : string = _name and public set value = _name <- value However when I try to access the properties of the F# version it just returns a compile error saying "Lookup on object of indeterminate type based on information prior to this program point. A type annotation may be needed prior to this program point to constrain the type of the object. This may allow the lookup to be resolved." The code thats trying to get the property is a part of my Repository (I'm using EF Code First). module Databasethings = let GetEntries = let ctx = new SevenContext() let mydbset = ctx.Set<MyTest>() let entries = mydbset.Select(fun item -> item.Name).ToList() // This line comes up with a compile error at "item.Name" (the compile error is written above) entries What the hell is going on? Thanks in advance!

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  • What are the default access rights for a process started with ShellExecuteEx?

    - by Heinrich Ulbricht
    I need to perform certain operation on a process started with ShellExecuteEx like waiting for it, duplicating handles, querying and setting information etc. Now I am wondering if I can do all these things on the hProcess member which is returned in the SHELLEXECUTEINFO structure I pass. Does anybody know this? Do I have rights like PROCESS_DUP_HANDLE, SYNCHRONIZE, PROCESS_SET_INFORMATION, PROCESS_QUERY_INFORMATION and so on by default?

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  • Inline function v. Macro in C -- What's the Overhead (Memory/Speed)?

    - by Jason R. Mick
    I searched Stack Overflow for the pros/cons of function-like macros v. inline functions. I found the following discussion: Pros and Cons of Different macro function / inline methods in C ...but it didn't answer my primary burning question. Namely, what is the overhead in c of using a macro function (with variables, possibly other function calls) v. an inline function, in terms of memory usage and execution speed? Are there any compiler-dependent differences in overhead? I have both icc and gcc at my disposal. My code snippet I'm modularizing is: double AttractiveTerm = pow(SigmaSquared/RadialDistanceSquared,3); double RepulsiveTerm = AttractiveTerm * AttractiveTerm; EnergyContribution += 4 * Epsilon * (RepulsiveTerm - AttractiveTerm); My reason for turning it into an inline function/macro is so I can drop it into a c file and then conditionally compile other similar, but slightly different functions/macros. e.g.: double AttractiveTerm = pow(SigmaSquared/RadialDistanceSquared,3); double RepulsiveTerm = pow(SigmaSquared/RadialDistanceSquared,9); EnergyContribution += 4 * Epsilon * (RepulsiveTerm - AttractiveTerm); (note the difference in the second line...) This function is a central one to my code and gets called thousands of times per step in my program and my program performs millions of steps. Thus I want to have the LEAST overhead possible, hence why I'm wasting time worrying about the overhead of inlining v. transforming the code into a macro. Based on the prior discussion I already realize other pros/cons (type independence and resulting errors from that) of macros... but what I want to know most, and don't currently know is the PERFORMANCE. I know some of you C veterans will have some great insight for me!!

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  • DataContractJsonSerializer generating Ghost string to JSON keys?

    - by Anil Namde
    DataContractJsonSerializer this is nice class added in the .net framework which can be used to serialize/desirealize object into JSON. Now following is the example i am trying [Serializable] class User { public string name; public string userId; } Now following is the output generated Output : Notice structure where only "name" is expected instead of k__BackingField Now this is the problem after digging so much i am not sure from where < and _BackingField is coming ? { "<name>k__BackingField":"test user", "<userId>k__BackingField":100001}

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  • Threadpool design question

    - by ZeroVector
    I have a design question. I want some feedback to know if a ThreadPool is appropriate for the client program I am writing. I am having a client running as a service processing database records. Each of these records contains connection information to external FTP sites [basically it is a queue of files to transfer]. A lot of them are to the same host, just moving different files. Therefore, I am grouping them together by host. I want to be able to create a new thread per host. I really don't care when the transfers finish, they just need to do all the work (or try to do) they were assigned, and then terminate once they are finished, cleaning up all resources they used in the process. I anticipate no more than 10-25 connections to be established. Once the transfer queue is empty, the program will simply wait until there are records in the queue again. Is the ThreadPool a good candidate for this or should I use a different approach? Edit: For the most part, this is the only significant custom application running on the server.

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  • How to wrap Ruby strings in HTML tags

    - by Jason H.
    Hi all: I'm looking for help on two things. 1) I'm looking for a way for Ruby to wrap strings in HTML. I have a program I'm writing that generates a Hash of word frequencies for a text file and I want to take the results and place it into an HTML file rather than print to STDOUT. I'm thinking each string needs to be wrapped in an HTML paragraph tag using readlines() or something, but I can't quite figure it out. Then, once I've wrapped the strings in HTML 2) I want to write to an empty HTML file. Right now my program looks like: filename = File.new(ARGV[0]).read().downcase().scan(/[\w']+/) frequency = Hash.new(0) words.each { |word| frequency[word] +=1 } frequency.sort_by { |x,y| y }.reverse().each{ |w,f| puts "#{f}, #{w}" } So if we ran a text file through this and received: 35, the 27, of 20, to 16, in # . . . I'd want to export to an HTML file that wraps the lines like: <p>35, the</p> <p>27, of</p> <p>20, to</p> <p>16, in</p> # . . . Thanks for any tips in advance!

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  • Java Out of memory - Out of heap size

    - by user1907849
    I downloaded the sample program , for file transfer between the client and server. When I try running the program with 1 GB file , I get the Exception in thread "main" java.lang.OutOfMemoryError: Java heap space at Client.main(Client.java:31). Edit: Line no 31: byte [] mybytearray = new byte [FILE_SIZE]; public final static int FILE_SIZE = 1097742336; // receive file long startTime = System.nanoTime(); byte [] mybytearray = new byte [FILE_SIZE]; InputStream is = sock.getInputStream(); fos = new FileOutputStream(FILE_TO_RECEIVED); bos = new BufferedOutputStream(fos); bytesRead = is.read(mybytearray,0,mybytearray.length); current = bytesRead; do { bytesRead = is.read(mybytearray, current, (mybytearray.length-current)); if(bytesRead >= 0) current += bytesRead; } while(bytesRead > -1); bos.write(mybytearray, 0 , current); bos.flush(); Is there any fix for this?

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  • Prototyping Qt/C++ in Python

    - by tstenner
    I want to write a C++ application with Qt, but build a prototype first using Python and then gradually replace the Python code with C++. Is this the right approach, and what tools (bindings, binding generators, IDE) should I use? Ideally, everything should be available in the Ubuntu repositories so I wouldn't have to worry about incompatible or old versions and have everything set up with a simple aptitude install. Is there any comprehensive documentation about this process or do I have to learn every single component, and if yes, which ones? Right now I have multiple choices to make: Qt Creator, because of the nice auto completion and Qt integration. Eclipse, as it offers support for both C++ and Python. Eric (haven't used it yet) Vim PySide as it's working with CMake and Boost.Python, so theoretically it will make replacing python code easier. PyQt as it's more widely used (more support) and is available as a Debian package. Edit: As I will have to deploy the program to various computers, the C++-solution would require 1-5 files (the program and some library files if I'm linking it statically), using Python I'd have to build PyQt/PySide/SIP/whatever on every platform and explain how to install Python and everything else.

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  • Is glDisableClientState required?

    - by Shawn
    Every example I've come across for rendering array data is similar to the following code, in which in your drawing loop you first call glEnableClientState for what you will be using and when you are done you call glDisableClientState: void drawScene(void) { glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT); glEnableClientState(GL_VERTEX_ARRAY); glEnableClientState(GL_TEXTURE_COORD_ARRAY); glBindTexture(GL_TEXTURE_2D, texturePointerA); glTexCoordPointer(2, GL_FLOAT, 0,textureCoordA); glVertexPointer(3, GL_FLOAT, 0, verticesA); glDrawElements(GL_QUADS, numPointsDrawnA, GL_UNSIGNED_BYTE, drawIndicesA); glBindTexture(GL_TEXTURE_2D, texturePointerB); glTexCoordPointer(2, GL_FLOAT, 0,textureCoordB); glVertexPointer(3, GL_FLOAT, 0, verticesB); glDrawElements(GL_QUADS, numPointsDrawnB, GL_UNSIGNED_BYTE, drawIndicesB); glDisableClientState(GL_TEXTURE_COORD_ARRAY); glDisableClientState(GL_VERTEX_ARRAY); } In my program I am always using texture coordinates and vertex arrays, so I thought it was pointless to keep enabling and disabling them every frame. I moved the glEnableClientState outside of the loop like so: bool initGL(void) { //... glEnableClientState(GL_VERTEX_ARRAY); glEnableClientState(GL_TEXTURE_COORD_ARRAY); } void drawScene(void) { glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT); glBindTexture(GL_TEXTURE_2D, texturePointerA); glTexCoordPointer(2, GL_FLOAT, 0,textureCoordA); glVertexPointer(3, GL_FLOAT, 0, verticesA); glDrawElements(GL_QUADS, numPointsDrawnA, GL_UNSIGNED_BYTE, drawIndicesA); glBindTexture(GL_TEXTURE_2D, texturePointerB); glTexCoordPointer(2, GL_FLOAT, 0,textureCoordB); glVertexPointer(3, GL_FLOAT, 0, verticesB); glDrawElements(GL_QUADS, numPointsDrawnB, GL_UNSIGNED_BYTE, drawIndicesB); } It seems to work fine. My question is: Do I need to call glDisableClientState somewhere; perhaps when the program is closed?. Also, is it ok to do it like this? Is there something I'm missing since everyone else enables and disables each frame?

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  • How to validate csv file ?

    - by Rachel
    How can we validate a CSV file ? I have an CSV file of structure: Date;Id;Shown 15-Mar-10;231;345 15-Mar-10;232;346 and so on and on !!! approx around 80,000 rows. How can I validate this CSV file before starting the parsing using fgetcsv ?

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  • XMLEncoder in java for serialization

    - by tom
    Im just wondering how i use xmlencoder to serialize ArrayList where foo is my own made class. Do i have to do anything in particular, ie define my own xml structure first and then call toString on each value in my list and write it out? Can anyone point me to a good tutorial? http://java.sun.com/products/jfc/tsc/articles/persistence4/ Thats what i have been looking at but it doesnt seem to mention what to do with non library classes. Thanks

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  • The way cores, processes, and threads work exactly?

    - by unknownthreat
    I need a bit of an advice for understanding how this whole procedure work exactly. If I am incorrect in any part described below, please correct me. In a single core CPU, it runs each process in the OS, jumping around from one process to another to utilize the best of itself. A process can also have many threads, in which the CPU core runs through these threads when it is running on the respective process. Now, on a multiple core CPU, Do the cores run in every process together, or can the cores run separately in different processes at one particular point of time? For instance, you have program A running two threads, can a duo core CPU run both threads of this program? I think the answer should be yes if we are using something like OpenMP. But while the cores are running in this OpenMP-embedded process, can one of the core simply switch to other process? For programs that are created for single core, when running at 100%, why the CPU utilization of each core are distributed? (ex. A duo core CPU of 80% and 20%. The utilization percentage of all cores always add up to 100% for this case.) Do the cores try help each other run each thread of each process in some ways? Frankly, I'm not sure how this works exactly. Any advice is appreciated.

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  • Just for fun (C# and C++)...time yourself [closed]

    - by Ted
    Possible Duplicate: What is your solution to the FizzBuzz problem? OK guys this is just for fun, no flamming allowed ! I was reading the following http://www.codinghorror.com/blog/2007/02/why-cant-programmers-program.html and couldn't believe the following sentence... " I've also seen self-proclaimed senior programmers take more than 10-15 minutes to write a solution." For those that can't be bothered to read the article, the background is this: ....I set out to develop questions that can identify this kind of developer and came up with a class of questions I call "FizzBuzz Questions" named after a game children often play (or are made to play) in schools in the UK. An example of a Fizz-Buzz question is the following: Write a program that prints the numbers from 1 to 100. But for multiples of three print "Fizz" instead of the number and for the multiples of five print "Buzz". For numbers which are multiples of both three and five print "FizzBuzz". SO I decided to test myself. I took 5 minutes in C++ and 3mins in c#! So just for fun try it and post your timings + language used! P.S NO UNIT TESTS REQUIRED, NO OUTSOURCING ALLOWED, SWITCH OFF RESHARPER! :-) P.S. If you'd like to post your source then feel free

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  • loop is cut one element of the array

    - by Walaa
    The problem is : Write a program that reads a number n and then declares an array of n elements. The program then fills the array with the first n numbers, where each number is two to the power of the previous. Finally, display array’s contents. My code : import java.util.*; public class Q1 { static Scanner scan = new Scanner (System.in); public static void main(String args [] ) { int num; int i = 0; System.out.println("Enter a number :"); num = scan.nextInt(); double [] a=new double[num]; a[0]= num ; for ( ;i<=a.length-1 ; i++) { a[i+1] = Math.pow(2,a[i]); System.out.println((int)(a[i]) ); } } } The error is : ----jGRASP exec: java Q1 Enter a number : 4 4 16 65536 Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 4 at Q1.main(Q1.java:16) ----jGRASP wedge2: exit code for process is 1. why it says that? And the number by user printed twice!

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  • Append Results from two queries and output as a single table.

    - by tHeSiD
    I have two queries that I have to run, I cannon join them But their resultant tables have the same structrure. For example I have select * from products where producttype=magazine select * from products where producttype = book I have to combine the result of these two queries, and then output it as one single result. I have to do this inside a stored procedure. PS These are just examples I provided, i have a complex table structure. The main thing is I cannot join them.

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  • deserializing multiple types from a stream

    - by clanier9
    I have a card game program, and so far, the chat works great back and forth over the TCPClient streams between host and client. I want to make it do this with serializing and deserializing so that I can also pass cards between host and client. I tried to create a separate TCPClient stream for the passing of cards but it didn't work and figured it may be easier to keep one TCPClient stream that gets the text messages as well as cards. So I created a class, called cereal, which has the properties for the cards that will help me rebuild the card from an embedded database of cards on the other end. Is there a way to make my program figure out whether a card has been put in the stream or if it's just text in the stream so I can properly deserialize it to a string or to a cereal? Or should I add a string property to my cereal class and when that property is filled in after deserializing to the cereal, i'll know it's just text (if that field is empty after deserializing i'll know it's a card)? I'm thinking a try catch, where it tries to deserialize to a string, and if it fails it will catch and cast as a cereal. Or am I just way off base with this and should choose another route? I'm using visual studio 2011, am using a binaryformatter, and am new to serializing/deserializing.

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