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  • Use auto_ptr in VC6 dll cause crash

    - by Yan Cheng CHEOK
    // dll #include <memory> __declspec(dllexport) std::auto_ptr<int> get(); __declspec(dllexport) std::auto_ptr<int> get() { return std::auto_ptr<int>(new int()); } // exe #include <iostream> #include <memory> __declspec(dllimport) std::auto_ptr<int> get(); int main() { { std::auto_ptr<int> x = get(); } std::cout << "done\n"; getchar(); } The following code run perfectly OK under VC9. However, under VC6, I will experience an immediate crash with the following message. Debug Assertion Failed! Program: C:\Projects\use_dynamic_link\Debug\use_dynamic_link.exe File: dbgheap.c Line: 1044 Expression: _CrtIsValidHeapPointer(pUserData) Is it exporting auto_ptr under VC6 is not allowed? It is a known problem that exporting STL collection classes through DLL. http://stackoverflow.com/questions/2451714/access-violation-when-accessing-an-stl-object-through-a-pointer-or-reference-in-a However, I Google around and do not see anything mention for std::auto_ptr. Any workaround?

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  • Strange problem with vectors.

    - by Catalin Dumitru
    I have a really strange problem with stl vectors in which the wrong destructor is called for the right object when I call the erase method if that makes any sense. My code looks something like this: for(vector<Category>::iterator iter = this->children.begin(); iter != this->children.end(); iter++) { if((*iter).item == item) { this->children.erase(iter); return; } ------------------------- } It's just a simple function that finds the element in the vector which has some item to be searched, and removes said element from the vector. My problem is than when the erase function is called, and thus the object which the iterator is pointing at is being destroyed, the wrong destructor is being called. More specific the destructor of the last element in the vector is being called, and not of the actual object being removed. Thus the memory is being removed from the wrong object, which will still be an element in the vector, and the actual object which is removed from the vector, still has all of it's memory intact. The costructor of the object looks like this: Category::Category(const Category &from) { this->name = from.name; for(vector<Category>::const_iterator iter = from.children.begin(); iter != from.children.end(); iter++) this->children.push_back((*iter)); this->item = new QTreeWidgetItem; } And the destructor Category::~Category() { this->children.clear(); if(this->item != NULL) { QTreeWidgetItem* parent = this->item->parent(); if(parent != NULL) parent->removeChild(this->item); delete this->item; } }

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  • Silverlight - how to render image from non-visible data bound user control?

    - by MagicMax
    Hello! I have such situation - I'd like to build timeline control. So I have UserControl and ItemsControl on it (every row represents some person). The ItemsControl contains another ItemsControl as ItemsControl.ItemTemplate - it shows e.g. events for the person arranged by event's date. So it looks as some kind of grid with dates as a column headers and e.g. peoples as row headers. ........................|.2010.01.01.....2010.01.02.....2010.01.03 Adam Smith....|......[some event#1].....[some event#2]...... John Dow.......|...[some event#3].....[some event#4]......... I can have a lot of persons (ItemsControl #1 - 100-200 items) and a lot of events occured by some day (1-10-30 events per person in one day) the problem is that when user scrolls ItemsControl #1/#2 it happened toooo sloooooowwww due to a lot of elements should be rendered in one time (as I have e.g. a bit of text boxes and other elements in description of particular event) Question #1 - how can I improve it? May be somebody knows better way to build such user control? I have to mention that I'm using custom Virtual panel, based on some custom Virtual panel implementation found somewhere in internet... Question #2 - I'd like to make image with help of WriteableBitmap and render data bound control to image and to show image instead of a lot of elements. Problem is that I'm trying to render invisible data bound control (created in code behind) and it has actualWidth/Height equals to zero (so nothing rendered). How can I solve it? Thank you very much for you help!

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  • best way to set up a VM for development (regarding performance)

    - by raticulin
    I am trying to set up a clean vm I will use in many of my devs. Hopefully I will use it many times and for a long time, so I want to get it right and set it up so performance is as good as possible. I have searched for a list of things to do, but strangely found only older posts, and none here. My requirements are: My host is Vista 32b, and guest is Windows2008 64b, using Vmware Workstation. The VM should also be able to run on a Vmware ESX I cannot move to other products (VirtualBox etc), but info about performance of each one is welcomed for reference. Anyway I guess most advices would apply to other OSs and other VM products. I need network connectivity to my LAN Guest will run many java processes, a DB and perform lots of file I/O What I have found so far is: HOWTO: Squeeze Every Last Drop of Performance Out of Your Virtual PCs: it's and old post, and about Virtual PC, but I guess most things still apply (and also apply to vmware). I guess it makes a difference to disable all unnecessary services, but the ones mentioned in 1 seem like too few, I specifically always disable Windows Search. Any other service I should disable?

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  • Why use bin2hex when inserting binary data from PHP into MySQL?

    - by Atli
    I heard a rumor that when inserting binary data (files and such) into MySQL, you should use the bin2hex() function and send it as a HEX-coded value, rather than just use mysql_real_escape_string on the binary string and use that. // That you should do $hex = bin2hex($raw_bin); $sql = "INSERT INTO `table`(`file`) VALUES (X'{$hex}')"; // Rather than $bin = mysql_real_escape_string($raw_bin); $sql = "INSERT INTO `table`(`file`) VALUES ('{$bin}')"; It is supposedly for performance reasons. Something to do with how MySQL handles large strings vs. how it handles HEX-coded values However, I am having a hard time confirming this. All my tests indicate the exact oposite; that the bin2hex method is ~85% slower and uses ~24% more memory. (I am testing this on PHP 5.3, MySQL 5.1, Win7 x64 - Using a farily simple insert loop.) For instance, this graph shows the private memory usage of the mysqld process while the test code was running: Does anybody have any explainations or reasources that would clarify this? Thanks.

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  • Cutting Ubuntu to the bone for Virtualbox VM

    - by Monty
    I've been looking around for a Linux variant which will install only the software I need rather than everything Ubuntu (for example) puts in by default. This is to create a virtual machine in Virtualbox which has bash, apache, python, perl, SQLite, openssh and a few other programs but nothing else. I'd prefer to go with Ubuntu if possible but another modern distro would do as well (I like using apt-get and yum rather than downloading/compiling etc). So far, I've tried: SuseStudio.com, which is probably the best so far. Pressing F4 to get the boot options on Ubuntu 9.10, but there is no minimal installation (I think there was once). Arch Linux, slightly confusing install procedure but I might go back and try again. Gentoo, started well but fairly soon the HD on the virtual machine went to 2Gb, even before the installation had started in earnest (I'd partitioned the disks is all). I realise there are various "small" Linuxes around like Puppy, Feather, DSL, etc, but they seem to be aimed at desktop users or as a techie's toolkit, and I want a small-as-possible server distro which can be managed with tools like apt or yum or similar. TIA for any advice you can offer! -- Monty

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  • New NSData with range of old NSData maintaining bytes.

    - by umop
    I have a fairly large NSData (or NSMutableData if necessary) object which I want to take a small chunk out of and leave the rest. Since I'm working with large amounts of NSData bytes, I don't want to make a big copy, but instead just truncate the existing bytes. Basically: NSData *source: < a few bytes I want to discard + < big chunk of bytes I want to keep NSData *destination: < big chunk of bytes I want to keep There are truncation methods in NSMutableData, but they only truncate the end of it, whereas I want to truncate the beginning. My thoughts are to do this with the methods: - getBytes:range: and - initWithBytesNoCopy:length:freeWhenDone: However, I'm trying to figure out how to manage memory with these. I'm guessing the process will be like this (I've placed ????s where I don't know what to do): void *buffer // Get range of bytes [source getBytes:buffer range:NSMakeRange(myStart, myLength)]; // Somehow (m)alloc the memory which will be freed up in the following step ????? // Release the source, now that I've allocated the bytes [source release]; // Create a new data, recycling the bytes so they don't have to be copied NSData destination = [[NSData alloc] initWithBytesNoCopy:buffer length:myLength freeWhenDone:YES]; Thanks for the help!

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  • Getting "[Microsoft][ODBC SQL Server Driver][SQL Server]Incorrect syntax near 'Microsoft.'

    - by brohjoe
    Hi Experts, I'm getting an error, "[Microsoft][ODBC SQL Server Driver][SQL Server]Incorrect syntax near 'Microsoft.' Here is the code: Dim conn As ADODB.Connection Dim rst As ADODB.Recordset Dim stSQL As String Public Sub loadData() 'This was set up using Microsoft ActiveX Data Components version 6.0. 'Create ADODB connection object, open connection and construct the connection string object which is the DSN name. Set conn = New ADODB.Connection conn.ConnectionString = "sql_server" conn.Open 'conn.Execute (strSQL) On Error GoTo ErrorHandler 'Open Excel and run query to export data to SQL Server. strSQL = "SELECT * INTO SalesOrders FROM OPENDATASOURCE(Microsoft.ACE.OLEDB.12.0;" & _ "Data Source=C:\Workbook.xlsx;" & _ "Extended Properties=Excel 12.0; [Sales Orders])" conn.Execute (strSQL) 'Error handling. ErrorExit: 'Reclaim memory from the cntection objects Set rst = Nothing Set conn = Nothing Exit Sub ErrorHandler: MsgBox Err.Description, vbCritical Resume ErrorExit 'clean up and reclaim memory resources. conn.Close If CBool(cnt.State And adStateOpen) Then Set rst = Nothing Set conn = Nothing End If End Sub

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  • J2ME cache issue

    - by kiennt
    I have to write a J2ME app to retrieve images from server and display in mobile phone. I have seen and test that Snaptu have a mechanism to cache image, event with 100 images (both normal size and zoom size). I wonder how they can do that? I though that those guys use rms to save image stream to data. But when i check in working folder of simulater( I use Windows XP and Sun Wireless Toolkit 3.0, the Emulator device i use to run my program is CLDC Device 1 - my working folder is C:\Document And Settings\Administrator\javame-sdk\3.0\work\6\appdb), i see some .db file. When i delete these files, i still can view cache image in my emulator???? I also thought that those guys use heap memory to save image. But it is not correct because when i set limit device memory is 2MB (like some mobile phones), and i load and view 100 images in zoom size, it didn't make OutOfMemory Error? It so weird. Any one can help me? Thanks

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  • Qt/MFC Migration Framework tool: properly exiting DLL?

    - by User
    I'm using the Qt/MFC Migration Framework tool following this example: http://doc.qt.nokia.com/solutions/4/qtwinmigrate/winmigrate-qt-dll-example.html The dll I build is loaded by a 3rd party MFC-based application. The 3rd party app basically calls one of my exported DLL functions to startup my plugin and another function to shutdown my application. Currently I'm doing nothing in my shutdown function. When I load my DLL in the 3rd party app the startup function is called and my DLL starts successfully and I can see my message box. However if I shutdown my plugin and then try to start it again I get the following error: Debug Error! Program: <my 3rd party app> Module: 4.7.1 File: global\qglobal.cpp Line: 2262 ASSERT failure in QWidget: "Widgets must be created in the GUI thread.", file kernel\qwidget.cpp line 1233 (Press Retry to debug the application) Abort Retry Ignore This makes me think I'm not doing something to properly shutdown my plugin. What do I need to do to shut it down properly? UPDATE: http://doc.qt.nokia.com/solutions/4/qtwinmigrate/winmigrate-walkthrough.html says: The DLL also has to make sure that it can be loaded together with other Qt based DLLs in the same process (in which case a QApplication object will probably exist already), and that the DLL that creates the QApplication object remains loaded in memory to avoid other DLLs using memory that is no longer available to the process. So I wonder if there is some problem where I need to somehow keep the original DLL loaded no matter what?

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  • Converting Makefile to Visual Studio Terminology Questions (First time using VS)

    - by Ukko
    I am an old Unix guy who is converting a makefile based project over to Microsoft Visual Studio, I got tasked with this because I understand the Makefile which chokes VS's automatic import tools. I am sure there is a better way than what I am doing but we are making things fit into the customer's environment and that is driving my choices. So gmake is not a valid answer, even if it is the right one ;-) I just have a couple of questions on terminology that I think will be easy for an experienced (or junior) user to answer. Presently, a make all will generate several executables and a shared library. How should I structure this? Is it one "solution" with multiple projects? There is a body of common code (say 50%) that is shared between the various executable targets that is not in a formal library, if that matters. I thought I could just set up the first executable and then add targets for the others, but that does not seem to work. I know I am working against the tool, so what is the right way? I am also using Visual C++ 2010 Express to try and do this so that may also be a problem if support for multiple targets is not supported without using Visual C++ 2010 (insert superlative). Thanks, this is really one of those questions that should be answerable by a quick chat with the resident Windows Developer at the water cooler. So, I am asking at the virtual water cooler, I also spring for a virtual frosty beverage after work.

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  • My app crashes after multiple rotates

    - by Ian Rae
    My app is crashing when I try and rotate it more than a couple of times. I first thought it was just the iPhone Simulator, so I loaded the app onto an iPod touch, and it crashed after fewer rotates in a row. I suspect it's a memory leak in one of my rotate methods. The only place I can think that the crash is being caused is in willRotateToInterfaceOrientation:duration:. The only two methods related to rotate that I've added/extended are shouldAutorotateToInterfaceOrientation: and willRotateToInterfaceOrientation:duration and I don't think it's the first because it only contains the two words: return YES;. Here is my willRotateToInterfaceOrientation:duration: method so you can review it and see where the possible memory leak is. -(void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)orientation duration:(NSTimeInterval)duration { UIFont *theFont; if ((orientation == UIInterfaceOrientationLandscapeLeft) || (orientation == UIInterfaceOrientationLandscapeRight)) { theFont = [yearByYear.font fontWithSize:16.0]; yearByYear.font = theFont; [theview setContentSize:CGSizeMake(460.0f, 635.0f)]; } else { theFont = [yearByYear.font fontWithSize:10.0]; yearByYear.font = theFont; [theview setContentSize:CGSizeMake(300.0f, 460.0f)]; } [theFont release]; } yearByYear is a UITextView theview is a UIScrollView if anyone has any idea of why my app is crashing, I would be greatly appreciative.

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  • Emulating Dynamic Dispatch in C++ based on Template Parameters

    - by Jon Purdy
    This is heavily simplified for the sake of the question. Say I have a hierarchy: struct Base { virtual int precision() const = 0; }; template<int Precision> struct Derived : public Base { typedef Traits<Precision>::Type Type; Derived(Type data) : value(data) {} virtual int precision() const { return Precision; } Type value; }; I want a function like: Base* function(const Base& a, const Base& b); Where the specific type of the result of the function is the same type as whichever of first and second has the greater Precision; something like the following pseudocode: template<class T> T* operation(const T& a, const T& b) { return new T(a.value + b.value); } Base* function(const Base& a, const Base& b) { if (a.precision() > b.precision()) return operation((A&)a, A(b.value)); else if (a.precision() < b.precision()) return operation(B(a.value), (B&)b); else return operation((A&)a, (A&)b); } Where A and B are the specific types of a and b, respectively. I want f to operate independently of how many instantiations of Derived there are. I'd like to avoid a massive table of typeid() comparisons, though RTTI is fine in answers. Any ideas?

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  • MFC CDialog not showing

    - by Jesus_21
    here is my problem : In my Solution, I have 2 projects, one is a lib in which I created a ressource file (mylib.rc) and a dialog template in it. Then I made a class which inherits CDialog and uses this template. But when I instantiate it and call DoModal(), nothing appends... here the code of my class, is something wrong with it ? MyDialog.h /*MyDialog.h*/ #pragma once #include "../../../resource.h" class MyDialog : public CDialog { enum {IDD=IDD_DLGTEMPLATE}; public: MyDialog(CWnd* pParent = NULL); virtual ~MyDialog(); protected: virtual BOOL OnInitDialog(); DECLARE_MESSAGE_MAP() private: afx_msg void OnBnClickedOk(); afx_msg void OnBnClickedCancel(); }; MyDialog.cpp /*MyDialog.cpp*/ #include "stdafx.h" #include "MyDialog.h" MyDialog::MyDialog(CWnd* pParent /*=NULL*/) : CDialog(IDD_DLGTEMPLATE, pParent) {} MyDialog::~MyDialog() {} BOOL MyDialog::OnInitDialog() { return TRUE; } BEGIN_MESSAGE_MAP(MyDialog, CDialog) ON_BN_CLICKED(IDOK, &MyDialog::OnBnClickedOk) ON_BN_CLICKED(IDCANCEL, &MyDialog::OnBnClickedCancel) END_MESSAGE_MAP() void MyDialog::OnBnClickedOk() { OnOK(); } void MyDialog::OnBnClickedCancel() { OnCancel(); }

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  • How can I randomly iterate through a large Range?

    - by void
    I would like to randomly iterate through a range. Each value will be visited only once and all values will eventually be visited. For example: class Array def shuffle ret = dup j = length i = 0 while j > 1 r = i + rand(j) ret[i], ret[r] = ret[r], ret[i] i += 1 j -= 1 end ret end end (0..9).to_a.shuffle.each{|x| f(x)} where f(x) is some function that operates on each value. A Fisher-Yates shuffle is used to efficiently provide random ordering. My problem is that shuffle needs to operate on an array, which is not cool because I am working with astronomically large numbers. Ruby will quickly consume a large amount of RAM trying to create a monstrous array. Imagine replacing (0..9) with (0..99**99). This is also why the following code will not work: tried = {} # store previous attempts bigint = 99**99 bigint.times { x = rand(bigint) redo if tried[x] tried[x] = true f(x) # some function } This code is very naive and quickly runs out of memory as tried obtains more entries. What sort of algorithm can accomplish what I am trying to do? [Edit1]: Why do I want to do this? I'm trying to exhaust the search space of a hash algorithm for a N-length input string looking for partial collisions. Each number I generate is equivalent to a unique input string, entropy and all. Basically, I'm "counting" using a custom alphabet. [Edit2]: This means that f(x) in the above examples is a method that generates a hash and compares it to a constant, target hash for partial collisions. I do not need to store the value of x after I call f(x) so memory should remain constant over time. [Edit3/4/5/6]: Further clarification/fixes.

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  • Python import error: Symbol not found, but the symbol <s>is</s> *is not* present in the file

    - by Autopulated
    I get this error when I try to import ssrc.spread: ImportError: dlopen(/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/ssrc/_spread.so, 2): Symbol not found: __ZN17ssrcspread_v1_0_67Mailbox11ZeroTimeoutE The file in question (_spread.so) includes the symbol: $ nm _spread.so | grep _ZN17ssrcspread_v1_0_67Mailbox11ZeroTimeoutE U __ZN17ssrcspread_v1_0_67Mailbox11ZeroTimeoutE U __ZN17ssrcspread_v1_0_67Mailbox11ZeroTimeoutE (twice because the file is a fat ppc/x86 binary) EDIT: okay, as James points out, the U means that the symbol is undefined but required by the object file. With some more digging I've noticed (where I should have looked first...) these linker errors during compilation: CC=g++ CXX=g++ g++-4.0 -arch ppc -arch i386 -isysroot /Developer/SDKs/MacOSX10.4u.sdk -fno-strict-aliasing -fno-common -dynamic -DNDEBUG -O3 -I../.. -I../.. -I/usr/local/include -I/Library/Frameworks/Python.framework/Versions/2.6/include/python2.6 -O2 -I/usr/local/include -std=c++98 -pipe -fno-gnu-keywords -fvisibility-inlines-hidden -o SsrcSpread.o -c SsrcSpread.cc CC=g++ CXX=g++ /bin/sh ../../libtool --tag=CXX --mode=link g++-4.0 -arch ppc -arch i386 -isysroot /Developer/SDKs/MacOSX10.4u.sdk -bundle -undefined dynamic_lookup -F/Library/Frameworks -framework Python \ -pthread -D_REENTRANT -pedantic -Wall -Wno-long-long -Winline -Woverloaded-virtual -Wold-style-cast -Wsign-promo -L../../ssrc -lssrcspread -L/usr/local/lib -ltspread-core -o _spread.so SsrcSpread.o mkdir .libs g++-4.0 -arch ppc -arch i386 -isysroot /Developer/SDKs/MacOSX10.4u.sdk -bundle -undefined dynamic_lookup -F/Library/Frameworks -framework Python -pthread -D_REENTRANT -pedantic -Wall -Wno-long-long -Winline -Woverloaded-virtual -Wold-style-cast -Wsign-promo -o _spread.so SsrcSpread.o -Wl,-bind_at_load -L/Dev/libssrcspread-1.0.6/ssrc /Dev/libssrcspread-1.0.6/ssrc/.libs/libssrcspread.a -L/usr/local/lib -ltspread-core ld: warning: in ~/Dev/libssrcspread-1.0.6/ssrc/.libs/libssrcspread.a, file was built for unsupported file format which is not the architecture being linked (ppc) ld: warning: in /Developer/SDKs/MacOSX10.4u.sdk/usr/local/lib/libtspread-core.dylib, file was built for unsupported file format which is not the architecture being linked (ppc) ld: warning: in /Dev/libssrcspread-1.0.6/ssrc/.libs/libssrcspread.a, file was built for unsupported file format which is not the architecture being linked (i386) ld: warning: in /Developer/SDKs/MacOSX10.4u.sdk/usr/local/lib/libtspread-core.dylib, file was built for unsupported file format which is not the architecture being linked (i386) I'm also not entirely sure that the 10.4 sdk is the right one for compiling python modules (but switching to 10.6 didn't seem to help).

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  • How can I create a horizontal table in a single foreach loop in MVC?

    - by GenericTypeTea
    Is there any way, in ASP.Net MVC, to condense the following code to a single foreach loop? <table class="table"> <tr> <td> Name </td> <% foreach (var item in Model) { %> <td> <%= item.Name %> </td> <% } %> </tr> <tr> <td> Item </td> <% foreach (var item in Model) { %> <td> <%= item.Company %> </td> <% } %> </tr> </table> Where model is a simple object: public class SomeObject { public virtual Name {get;set;} public virtual Company {get;set;} } This would output a table as follows: Name | Bob | Sam | Bill | Steve | Company | Builder | Fireman | MS | Apple | I know I could probably use an extension method to write out each row, but is it possible to build all rows using a single iteration over the model? This is a follow on from this question as I'm unhappy with my accepted answer and cannot believe I've provided the best solution.

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  • How to genrate a monochrome bit mask for a 32bit bitmap

    - by Mordachai
    Under Win32, it is a common technique to generate a monochrome bitmask from a bitmap for transparency use by doing the following: SetBkColor(hdcSource, clrTransparency); VERIFY(BitBlt(hdcMask, 0, 0, bm.bmWidth, bm.bmHeight, hdcSource, 0, 0, SRCCOPY)); This assumes that hdcSource is a memory DC holding the source image, and hdcMask is a memory DC holding a monochrome bitmap of the same size (so both are 32x32, but the source is 4 bit color, while the target is 1bit monochrome). However, this seems to fail for me when the source is 32 bit color + alpha. Instead of getting a monochrome bitmap in hdcMask, I get a mask that is all black. No bits get set to white (1). Whereas this works for the 4bit color source. My search-foo is failing, as I cannot seem to find any references to this particular problem. I have isolated that this is indeed the issue in my code: i.e. if I use a source bitmap that is 16 color (4bit), it works; if I use a 32 bit image, it produces the all-black mask. Is there an alternate method I should be using in the case of 32 bit color images? Is there an issue with the alpha channel that overrides the normal behavior of the above technique? Thanks for any help you may have to offer! ADDENDUM: I am still unable to find a technique that creates a valid monochrome bitmap for my GDI+ produced source bitmap. I have somewhat alleviated my particular issue by simply not generating a monochrome bitmask at all, and instead I'm using TransparentBlt(), which seems to get it right (but I don't know what they're doing internally that's any different that allows them to correctly mask the image). It might be useful to have a really good, working function: HBITMAP CreateTransparencyMask(HDC hdc, HBITMAP hSource, COLORREF crTransparency); Where it always creates a valid transparency mask, regardless of the color depth of hSource. Ideas?

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  • What is the best way to iterate over a large result set in JDBC/iBatis 3?

    - by paul_sns
    We're trying to iterate over a large number of rows from the database and convert those into objects. Behavior will be as follows: Result will be sorted by sequence id, a new object will be created when sequence id changes. The object created will be sent to an external service and will sometimes have to wait before sending another one (which means the next set of data will not be immediately used) We already have invested code in iBatis 3 so an iBatis solution will be the best approach for us (we've tried using RowBounds but haven't seen how it does the iteration under the hood). We'd like to balance minimizing memory usage and reducing number of DB trips. We're also open to pure JDBC approach but we'd like the solution to work on different databases. UPDATE: We need to make as few calls to DB as possible (1 call would be the ideal scenario) while also preventing the application to use too much memory. Are there any other solutions out there for this type of problem may it be pure JDBC or any other technology? Thanks and hope to hear your insights on this.

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  • Using WCF to expose underlying process

    - by Steven
    I think I must be a little dull because I'm having so much difficulty with this. I use WCF for pretty much everything in-house, it's the most appropriate technology. I have a new Silverlight 3 app that is connecting to the WCF service and that's working fine. Where the problem begins is: Because of the expense in creating the objects within this service and the high correlation of individual objects being shared between clients I want to have a console application that basically gathers/calculates/caches all the data for the service 24/7 and the service basically connects to the console app (or whatever it is) and gets the pre-processed data. eg, think of it in terms of a stock reporting app (which it is). Person A has a portfolio of x, y z Person B has a portfolio of x, q, z, r The service needs to provide updated metrics on how their portfolio is performing. So instead of every 1 second processing person A, then person B, the app independently gathers the stock price and persons position information into memory and the service just queries the in memory result. Thanks for your help, I really am feeling dumb right now.

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  • What ORM for .NET should I use?

    - by eKek0
    I'm relatively new to .NET and have being using Linq2Sql for a almost a year, but it lacks some of the features I'm looking for now. I'm going to start a new project in which I want to use an ORM with the following characteristics: It has to be very productive, I don't want to be dealing with the access layer to save or retrieve objects from or to the database, but it should allows me to easily tweak any object before actually commit it to the database; also it should allows me to work easily with a changing database schema It should allows me to extend the objects mapped from the database, for example to add virtual attributes to them (virtual columns to a table) It has to be (at least almost) database agnostic, it should allows me to work with different databases in a transparent way It has to have not so much configuration or must be based on conventions to make it work It should allows me to work with Linq So, do you know any ORM that I could use? Thank you for your help. EDIT I know that an option is to use NHibernate. This appears as the facto standard for enterprise level applications, but also it seems that is not very productive because its deep learning curve. In other way, I have read in some other post here in SO that it doesn't integrate well with Linq. Is all of that true?

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  • Issues Deploying ROOT Context in Tomcat6

    - by Josh K
    I'm working on getting an application deployed to the ROOT ("/") context in my Tomcat 6 instance. Here's what has been done: Defined another virtual host (domain.com) Created the respective folder (/etc/tomcat6/Catalina/domain.com) Set it to auto deploy WAR's Set appBase to CATALINA_BASE/domainapps and created respective folder Copied manager.xml from localhost to domain.com. Now I'm trying to deploy into the ROOT context by uploading a ROOT.war to CATALINA_BASE/domainapps. This isn't working. I don't get any exceptions thrown, but the stock ROOT page ("It works !") stays up. I have successfully deployed it into another context (by uploading domainapp.war and viewing at /domainapp), but not ROOT. Re-reading the Virtual Host setup it makes reference to CATALINA_HOME and CATALINA_BASE. My CATALINA_HOME is at /usr/share/tomcat6/domainapp while CATALINA_BASE is /var/lib/tomcat6. Which should I be using for what? Currently haven't touched CATALINA_HOME but will try messing with a few things there. A better question might be what is the generally accepted flow taken to setup a new Tomcat instance and deploy an application to the root context.

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  • How To Find Reasons of Why Site Goes Online/Offline

    - by HollerTrain
    Seems today a website I manage has been going online and offline throughout the entire day. I have no idea what is causing the issue so I am seeking guidance on where to start. It is a Wordpress based site. So here is what I DO know: I use a program that pings the server every minute and when the server is not responding me it emails me, so I can know exactly when the site is online and offline. The site between 8pm to 12pm 12.28, and around the 1a hour early morning 12.29 (New York City timezone, and all times below are in same timezone). At the time of the ups/downs I see a lot of strain on the memory usage. Look at the load average when the site is going online/offline (http://screencast.com/t/BRlfXkqrbJII). Then I ran this command to restart http (http://screencast.com/t/usVtYWZ2Qi) and the memory usage then goes down to this (http://screencast.com/t/VdTIy3bgZiQB). An hour after I restarted http, the site then went offline/online so restarting the http didn't do much help. When the site is going offline/online, I ran the top command and get this (http://screencast.com/t/zEwr7YQj3). Here is a top command when the site is at it's lowest (http://screencast.com/t/eaMfha9lbT - so this would be dubbged "normal"). Here is a bandwidth report (http://screencast.com/t/AS0h2CH1Gypq). The traffic doesn't seem to be that much (http://screencast.com/t/s7hrWNNic1K), but looking at my times the site is going up/down this may be one of the reasons? I have the dvp Nitro package at Media Temple (http://mediatemple.net/webhosting/nitro/). So at this point I would request some help in trying to figure out what the cause of this is, and how I can go about pinpointing this issue. ANY HELP is greatly appreciated.

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  • In WMI, can I use a join (or something similar) to acquire the IisWebServer object for a site, given

    - by Precipitous
    Given a server name and a physical path, I'd like to be able to hunt down the IISWebServer object and ApplicationPool. Website url is also an acceptable input. Our technologies are IIS 6, WMI, and access via C# or Powershell 2. I'm certain this would be easier with IIS 7 its managed API. We don't have that yet. Here's what I can do: Get a list of IIS virtual directories from IISWebVirtualDirSetting and filter (offline) for the matching physical path. $theVirtualDir = gwmi -Namespace "root/MicrosoftIISv2" ` -ComputerName $servername -authentication PacketPrivacy ` -class "IISWebVirtualDirSetting" ` | where-object {$_.Path -like $deployLocation} From the virtual directory object, I can get a name (like W3SVC/40565456/root). Given this name, I can get to other goodies, such as the IIS web server object. gwmi -Namespace "root/MicrosoftIISv2" ` -ComputerName $servername ` -authentication PacketPrivacy ` -Query "SELECT * FROM IisWebServer WHERE Name='W3SVC/40589473'" The questions, restated: 1) This is a query language. Can I join or subquery so that 1 WMI query statement gets web servers based on IISWebVirtualDir.Path? How? 2) In solving 1, you'll have to explain how to query on the Path property. Why is this an invalid query? "SELECT * FROM IISWebVirtualDirSetting WHERE Path='D:\sites\globaldominator'"

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  • Lightweight alternative to Manual/AutoResetEvent in C#

    - by sweetlilmre
    Hi, I have written what I hope is a lightweight alternative to using the ManualResetEvent and AutoResetEvent classes in C#/.NET. The reasoning behind this was to have Event like functionality without the weight of using a kernel locking object. Although the code seems to work well in both testing and production, getting this kind of thing right for all possibilities can be a fraught undertaking and I would humbly request any constructive comments and or criticism from the StackOverflow crowd on this. Hopefully (after review) this will be useful to others. Usage should be similar to the Manual/AutoResetEvent classes with Notify() used for Set(). Here goes: using System; using System.Threading; public class Signal { private readonly object _lock = new object(); private readonly bool _autoResetSignal; private bool _notified; public Signal() : this(false, false) { } public Signal(bool initialState, bool autoReset) { _autoResetSignal = autoReset; _notified = initialState; } public virtual void Notify() { lock (_lock) { // first time? if (!_notified) { // set the flag _notified = true; // unblock a thread which is waiting on this signal Monitor.Pulse(_lock); } } } public void Wait() { Wait(Timeout.Infinite); } public virtual bool Wait(int milliseconds) { lock (_lock) { bool ret = true; // this check needs to be inside the lock otherwise you can get nailed // with a race condition where the notify thread sets the flag AFTER // the waiting thread has checked it and acquires the lock and does the // pulse before the Monitor.Wait below - when this happens the caller // will wait forever as he "just missed" the only pulse which is ever // going to happen if (!_notified) { ret = Monitor.Wait(_lock, milliseconds); } if (_autoResetSignal) { _notified = false; } return (ret); } } }

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