Archive for the ‘Visual studio’ Category

How to clear visual studio search history?

July 15, 2009 1 comment

Previous search terms of visual studio is stored in windows registry. The registry key for Visual Studio 9.0 is …


The search terms are arranged as …

Find 0
Find 1
Find 2

Delete them to clear search history.

auto keyword redefined in VC10

auto keyword is one of those keywords that’s never used. So what the c++ committee has done is, they’ve started using it for a better purpose. For better understanding see this simple demo…

First without using auto keyword…

void AutoTest()
  typedef std::vector<int> IntVector;
  IntVector Ints;
  std::generate_n(std::back_inserter( Ints ), 100, rand);

  // After filling some elements into the vector, we iterate through them
  for( IntVector::iterator Itr = Ints.begin(); Itr != Ints.end(); ++Itr )
    // Some code

Now let’s try with the auto keyword…

void AutoTest()
  typedef std::vector</int><int> IntVector;
  IntVector Ints;
  std::generate_n(std::back_inserter( Ints ), 100, rand);

  // After filling some elements into the vector, we iterator through them
  for( auto Itr = Ints.begin(); Itr != Ints.end(); ++Itr )
    // Some code

Hope you noticed the difference, the type for the variable Itr is automagically inferred by the compiler based on the return type from Ints.begin().  Another huge benefit is when using auto keyword to wrap a lamda  expression (an anonymous/inline functor). See this example…

void LamdaTest()
int x = 0;
auto LamdaFunc = [&x](int y)
while( y– > 0 )

LamdaFunc( 10 );
LamdaFunc( 100 );

std::cout < < "Value of x after calling LamdaFunc is: " << x; }[/sourcecode] For us it's hard to infer or to know how to declare the type of this lamda expression but for the compiler it's easy (well hope so). When we give auto keyword the type is auto inferred. We then use LamdaFunc object to invoke this lamda expression. In the end x will have the value 110. Note that the expression [&x] means, pass x by reference. I'll brag about lamda's in my next post probably. Cool isn't it, I liked this feature. 8)

Ordering output of out of order builds in Visual Studio

June 2, 2009 1 comment

So what is an out of order build?

If you’ve got a multi-core processor then your compilation process will be distributed between these processors. One project will be built on one core while another one on a different core. Then all of these obj file will be gathered together during linking.

But one problem is that the output will look mangled, see this output…

Out of order builds

Out of order builds

The numbers on the left 3>, 4> uniquely identify a particular project being compiled. I’ve got two cores so effectively two projects can be compiled in parallel. But this is a mess particularly if you’ve got too many project’s you’ll have a hard time find out related projects, you’ll get tired of scrolling up and down. 🙂

But there is a way to overcome this, at the top of the output window (see above shot) there is a combo “Show output from:”. Change this to “Build Order” from “Build”, now this is how the output will look…

Build output ordered

Build output ordered

Just to be complete; you can enable out of order builds via…

Tools->Options->Projects and Solutions->Build and Run->Maximum number of parallel project builds.

Here is a screenshot of this dialog.

Enable Out Of Order Builds

Enable Out Of Order Builds

So enjoy working in this great IDE (well) ;).

Project Conversion Bug in VS2008

May 11, 2009 1 comment

Are you having trouble with VS2008 after conversion from VS2005 to VS2008? Most common complaints are that the executable is way to slow when compared to it’s counterpart generated with VS2005. The reason for this is given in this MSDN forum thread have a look…

The essence of this thread is given below (quote from the thread, thanks to Jon Baggott)…

In Visual Studio 2008 SP1 (SP1 not RTM) there is a serious bug with /O2 optimization. One way this bug can be triggered is by upgrading a project from a previous version. Even though the project setting shows the release build is set to /O2, the build can be not optimized at all. To work around it you have to change the setting to no optimization, apply, and then change it back to /O2. The quick way to see if this is needed is to check whether the setting for optimization is in bold or regular – if’s it’s bold you’re OK; if it’s regular text you’re not. This bug has been reported to Microsoft by many people over the past few months via the Connect feedback site but every case has been closed by them without doing anything and for completely invalid reasons.

Breakpoints in Visual Studio

May 2, 2009 4 comments

What’s a breakpoint?

A breakpoint is defined as the location where a debugger breaks execution to allow the user to have a look or to modify the execution context.

What’s new with breakpoints?

With visual studio 2005 and 2008 behavior of breakpoint has changed. Some features that were added are as follows…

  1. Know hit count of a break point, no more need to keep a temp debugger variable for counting hits. For e.g. you can set a conditional breakpoint and then enable hit count. You’ll see how many times the condition was satisfied, you can also disable breaking of execution so that the program keeps running.
  2. Trace local variables/function name and more to the visual studio immediate/output window.
  3. Run a macro when a breakpoint is hit.
  4. We can disable breaking of execution which means there will only be tracing going on and no breaking of execution.

So to access these features, after adding a breakpoint, open the breakpoint window and right click on this breakpoint. Lower half of the dropdown contains these features, here is a screenshot of the context menu…

Breakpoint Context Menu

Breakpoint Context Menu

There are different types of break points available in visual studio. There are four in my knowledge…

  1. File breakpoint – Breaks at a location in a file
  2. Address breakpoint – Breaks at an address
  3. Function breakpoint – Breaks at a function
  4. Data breakpoint – Breaks at specific byte locations

Hit count

Let me show you how to count the number of even numbers from 1 to 100, I know it’s quite easy, it’s fifty, but via debugger? Here is a small function with a loop from 1 to 100.

void CountEven( const int From, const int To )
   for( int Index = From; Index < To; ++Index )
      // Set a conditional breakpoint to get the count of odd numbers,
      // Dummy code to allow set a breakpoint
      ::SendMessage( AfxGetMainWnd()->GetSafeHwnd(), WM_NULL, 0, 0 );

Now set a break point inside the for loop (Press F9) and right click and select “Breakpoint->Condition” item. You’ll get the following dialog…

Setting a Conditional breakpoint

Setting a Conditional breakpoint

So here I’ve set the condition that whenever Index%2 is zero then we have an even number. So when this happens I’m asking the debugger to break execution. So this works as expected but our aim is to count the number of even numbers using debugger, so for that again right click on the breakpoint line and select “Breakpoint->Hit Count” item, following dialog pops up…

Enable hit count in the debugger

Enable hit count in the debugger

You can see that I’ve selected an option called “break when the hit count is a multiple of”. I’ve given 10 as the option, so that frequency of breaking of execution is less. When I run the code this is what I get in the breakpoints window…

Hit count result

Hit count result

See the “Hit Count” item?  Execution broke 5 times this means for every 10 hits, hence count is 50. Isn’t this fun?


Remember the times when we had to trace statements just for debugging purpose, for e.g. we wanted to trace a certain variable’s value when it satisfies a condition. Let’s take the above example, we’ve already enabled a conditional breakpoint such that it’s breaks execution whenever “Index” is an even number. Right click on the breakpoint line and select “Breakpoint” and then “When Hit” option. Following dialog pops up…

When Hit Dialog

When Hit Dialog

Check the first option Print a message”, this is the option that prints a message either to your “immediate window” or to your “Output window” based on the options that you’ve set. Now run the program to have some fun, this is the output in my computer…

Output of "when hit"

Output of "when hit"

All even index values are traced to the output window, isn’t this cool?


This one is even more cool. It allows us to set breakpoint filters. This is kind of a conditional but with a larger scope. For e.g. if you want to break execution only for a certain thread or only for a certain process. So for this right click on the breakpoint line and select “Breakpionts->Filter”. Following dialog pops up…

Breakpoint filter

Breakpoint filter

Pretty easy to use. So this means for a function that is called from multiple threads you can explicitly tell the debugger for which threads to break execution.

Tid bits

  1. Did you know that you can set a breakpoint in the call stack window by press F9?
  2. Did you know that you can delete all breakpoints by press Ctrl + Shift + F9?
  3. Did you know that you can run to cursor by pressing Ctrl + F10?
  4. Did you know that you display breakpoints window by pressing Alt + F9?
  5. Did you know that you can use “Set Next Statement” by pressing Ctrl + Shift + F10?

Yeap that’s it from me for now, all the best. 🙂

Script error in VC++ wizards after installing IE8

April 1, 2009 3 comments

You might have script errors in VC++ wizards after installing IE8, for e.g. when you double click inside a dialog normally we should taken to corresponding file but instead we get a script error…

Script error

Script error

Pretty strange isn’t it. Well as per VC++ team blogs this bug due to IE8 installation. Reason for this behavior is as explained below (quoted from VC++ team blogs…)

The VC++ Wizards Engine implements the IInternetSecurityManager interface.  In this implementation it allows or disallows specific actions under certain policies that Internet Explorer queries it about.  In IE8 a custom Security Manager now also gets queried about the URLACTION_ACTIVEX_OVERRIDE_REPURPOSEDETECTION policy which IE previously did not delegate to custom security managers when the engine wasn’t running in the iexplore.exe process.  The IE engine then fails this action because we don’t have a policy entry for it in the custom zone for VC++ Wizards. We are still investigating whether this change in IE8 is by design and will possibly be addressing it by a fix in either the Wizard or IE components depending on the outcome.

And according to this blog, following fix should work….

Please follow the following steps:
  • Open regedit (on a 64-bit OS, open the 32-bit regedit)
  • Under “HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet
    Settings\Zones”, create a new key called 1000 (if it isn’t already there)
  • Under 1000, create a DWORD entry with:
    • o Name = 1207
    • o Type = REG_DWORD
    • o Data = 0x000000

Just now I had this problem hence I had to use this fix and it works. 🙂

Debugging WM_PAINT messages

November 15, 2008 1 comment

It’s always irritating to debug paint messages and sometimes expensive too. I’ve tried different methods to try debug painting issues, always ended up disappointed.

Why is it such a pain to debug WM_PAINT messages?

Main reason is, we are not in control. Paint messages comes via a window framework. Painting is done whenever a window gains focus or is activated this means our application will never get focus if we set a breakpoint in an OnPaint function because as soon as our application comes to focus it again sends a repaint request which again breaks into the OnPaint function.

It’s can be expensive too because we’ll need some kind of a dual monitor setup. So that our application runs on one monitor and the debugger on the other. For professional game/UI developers it’s ok because that’s their job and they will always need such a setup. But guys like me cannot affort such a setup.

Any workaround?

Yes, that’s the good news. Windows explorer has a cute feature called “Tile Horizontally” and “Tile Vertically”. It also has another feature to select taskbar items using control key.

So this is how a standar taskbar looks, as you already know that at a time, in windows, only one window can be active.


The tab having a dark shade is the one that’s active, and if you right click on this tab you’ll get a context menu which will correspond to the active application’s system menu.

Now here is the interesting part use ‘Ctrl’ key to select multiple tabs. Press ‘Ctrl’ and then use your mouse to click on tabs you wanna select and then right click on any of these selected tabs and see what you get! Here is a screenshot of what I get…


These menu items are interesting, most windows users are unaware of this option, it’s a quick way to arrange your windows. You can try them one by one. Note that there is an option to close a group too. 🙂

So returning back to our original discussion, we now apply this trick to our application. We are going to select visual studio and an application that’s being debugged. I’ve set a break point in the OnPaint function.

So we select both applications in the taskbar using ‘Ctrl’ key and mouse and then right click and select ‘Tile vertically’ or ‘Tile Horizontally’. I would select ‘Tile vertically’ as it would give me enough vertical space but you can decide what’s best for you. Eventually what I get is a screen like this with two windows that doesn’t overlap each other. One of them is visual studio and the other one is my application that’s being debugged, also note that I’ve set a breakpoint in OnPaint function. Both applications behave independently without interfering with each other.


Now my desktop acts like a dual monitor setup. 😉 It’s kinda cool for debugging purpose and yeah I agree this is not the ultimate solution but it’s quite useful. Hope this helps you. 🙂

How to debug a dll?

October 25, 2008 5 comments


Well debugging exe is quite easy, but ever wondered how to debug a dll. Well why? Simple, you write a dll and you wanna debug a bug just like you would do with an executable.

Can you give us some examples?

Well so what is a dll? I think of it as a parasite because just like a parasite it’s dependent on an executable to get it running. Some examples follow…

  1. A good example to think of will be rundll32.exe. Ever thought about that name “rundll32.exe”, it just means “run a 32 bit dll using this exe”, so how does this achieve this, remember the command line that we pass to it, i.e. name of the dll followed by a procedure name exported from our dll.
  2. Another example to think of is regsvr32.exe, does the same stuff i.e. registers a COM dll but this time with a difference, we don’t have to give a procedure name. Because COM programming protocol defines mandatory functions to be exported from a COM dll and regsvr32.exe knows exactly which function to call based on the command line switches passed in.
  3. Another example that comes to mind is the windows surrogate process “dllhost.exe”, I’ve heard people say that it’s a virus ;). Naah it’s a COM surrogate process which helps in hosting a COM dll to make the dll behave like a process hence providing the flexibility to behave like an executabable and at the same time like a dll, vice versa is not possible. Well it can at times be hosting a malicious dll too. It’s quite rare though.

What has this got to do with debugging a DLL?

The reason why I’ve given above examples is to help you understand that a DLL cannot run by itself, it needs a host process to help it run.

Exactly! same for debugging it needs a process to get it running so that execution reaches our breakpoint that we’ve set. Aha! so there must be some option to tell the debugger about the host process. Oh yeah, goto Project settings->Debugging->Executable for Debug Session. Select any process which is using your dll.

Think that you are writing a window’s shell extension, which are dlls, think on how to debug them. So for this case your target process will be explorer.exe. So you will specify explorer.exe as your process. Or imagine writing an activex control, so for this case the target process will be an activex test container.

This is a shot from VC6, it’s quite similar in VC7, VC8 and VC9, instead of tabs there you have a tree menu holding the “Debugging” item right at the top of the tree.

Well now just press F5 and see what happens, you will see your target process running and just try doing a button or menu click that could invoke the function in which you’ve set a breakpoint.  If you are writing a shell extension for e.g. extending shell context menu, then you would right click on a file in the explorer window.

Also note that if your active project is a ‘dll project’ then you’ll get prompted to enter a target process name to get the dll hosted as soon as you press F5. So no need to go to project properties.

Hope this helps you?

Redistributables for different VC versions starting from VC 2005

August 29, 2008 Leave a comment

If you want to re-distribute the applications that you developed in different versions of VC then you need to install their redist packages on such target machines, following are the redists that I use…

  1. Redistributable for VC 2005 applications is here
  2. Redistributable for VC 2008 applications is here
  3. Redistributable for VC 2008 feature pack applications is here
  4. Redistributable for VC 2008 service pack 1 applications is here

Also if you are interested there is already a redist folder in your VS installation directory, which contains dlls meant for redistribution.

How to know the level of service pack installed for VS6?

August 26, 2008 Leave a comment

It’s here…


For me the REG_DWORD(latest) value says 6, and the REG_SZ value says sp6.

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