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Pavel Vozenilek wrote: BOOST_FOREACH, a C++ library solution
I know
However, BOOST_FOREACH is not going into C++ 0x.
My programming blahblahblah blog. If you ever find anything useful here, please let me know to remove it.
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> However, BOOST_FOREACH is not going into C++ 0x.
I'd heard some noises that this library solution (and its horrible complexity inside) may serve as proof of feasability and as s hint of real world need, helping to get "native" construct into the language. If that ever happens it'll be years and years from now, though.
The BOOST_FOREACH works with current compilers (even BCB & VC6).
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One of the language features that are likely to get included into the next version of the standard is type inference. Namely, if the compiler can deduce the type of the variable, we can declare it with keyword auto :
auto i = 1;
Many people confuse type inference with variant types, but it is not the case. In the sample above, i is declared as int , not variant . In other words, it is exactly equivalent to:
int i = 1;
Type inference is also going to be included in C# 3.0, but the choice of the keyword is very unfortunate: var . For instance the same construct:
var i = 1;
means one thing in JavaScript (i is variant ) and another in C# (i is int )
How is this useful? It can save us a lot of typing, and annoying syntax errors. Say we have:
vector<int> v;
vector<int>::iterator b = v.begin();
auto e = v.end();
For more information, see the official proposal document.[^]
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i simply don't like this kind of things...
when a programmer knows what he does, yes, it can be safely hidden and the choice can be let to the compiler, but what i see is that rarely programmers (mostly beginners, but hey, programmers anyway) know exactly what the compiler does with their code (implicit conversions, implicit operators calls, etc...).
if we let the choice to the compiler to choose the most appropriated type to a variable, such as variants, then we will loose the power - i fell - of C++, joining the VB road...
Nemanja Trifunovic wrote: How is this useful? It can save us a lot of typing, and annoying syntax errors. Say we have:
as i was saying, just know what you do while code, and everything should be ok...
moreover, don't auto keyword already mean something specific within the C++ language ?!
TOXCCT >>> GEII power [toxcct][VisualCalc 2.20][VCalc 3.0 soon...]
-- modified at 5:58 Tuesday 31st January, 2006
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toxcct wrote: if we let the choice to the compiler to choose the most appropriated type to a variable, such as variants, then we will loose the power - i fell - of C++, joining the VB road...
But there is a big difference: C++ is still statically typed language, and type inference does not mean variants. If someone makes a mistake about the infered type, he will be greeted by a compiler error. With variants, one would end up with a run-time error, which is much worse.
My programming blahblahblah blog. If you ever find anything useful here, please let me know to remove it.
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In general, I try to be somewhat conservative when it comes to adopting new technologies in production work. Sure, it is important to stay informed and try all the latest buzz, but for the work that actually brings food to the table I prefer widely adopted and well tested tools.
Having said all that, I spent last couple of days porting the client side of a distributed linguistic application from VC++ 6.0 to VC++ 8.0 (aka VC++ 2005), and the later was released a couple of weeks ago. That was a two-step operation: first I did the port from 6.0 to 7.1 which I know very well, and once it compiled there, another step was from 7.1 to 8.0.
It was somewhat surprising how many errors appeared in the second step. Most of them actually come from unstandard programming practices that originate in VC 6.0, but were tolerated in VC 7.1 (declarations within for loops, wchar_t a typedef for unsigned short,...), but some of them are really surprising. For instance, I found out that some libraries (xalan, crypto++) compile fine in Release mode, but in compile mode they report compile error C2678 somewhere from xutility. The solution is not exactly obvious: adding a preprocessor definition _HAS_ITERATOR_DEBUGGING=0.
All in all, I like VC 2005 so far. The compiler is better, and IDE has some nice new features: Error window, graying out "ifdef-ed" code, Intelisense is better than ever. The interesting question is C++/CLI. Is it going to be adopted among developers? I wish it did, but frankly it would surprise me: C++ developers don't need .NET, and .NET developers don't know what to do with C++.
My programming blahblahblah blog. If you ever find anything useful here, please let me know to remove it.
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I was very impressed to find your code for gcstl.h, but when I try it with Visual Studio 2005, I get these errors:
----------------------------------------------------------------------
C:\spring2007\STL\gcstl>cl /clr:oldSyntax *.cpp
Microsoft (R) C/C++ Optimizing Compiler Version 14.00.50727.42
for Microsoft (R) .NET Framework version 2.00.50727.42
Copyright (C) Microsoft Corporation. All rights reserved.
test_gcstl.cpp
C:\Program Files\Microsoft Visual Studio 8\VC\INCLUDE\xutility(2282) : warning C
4996: 'std::_Copy_opt' was declared deprecated
C:\Program Files\Microsoft Visual Studio 8\VC\INCLUDE\xutility(2270) : s
ee declaration of 'std::_Copy_opt'
Message: 'You have used a std:: construct that is not safe. See document
ation on how to use the Safe Standard C++ Library'
test_gcstl.cpp(25) : see reference to function template instantiation '_
OutIt std::copy<std::_vector_iterator<_ty,_alloc>,textwriter_iterator<t>>(_InIt,
_InIt,_OutIt)' being compiled
with
[
_OutIt=textwriter_iterator<system::string __gc="" *="">,
_Ty=gcroot<system::string __gc="" *="">,
_Alloc=std::allocator<gcroot<system::string __gc="" *="">>,
T=System::String __gc *,
_InIt=std::_Vector_iterator<gcroot<system::string __gc="" *="">,std::alloc
ator<gcroot<system::string __gc="" *="">>>
]
Microsoft (R) Incremental Linker Version 8.00.50727.42
Copyright (C) Microsoft Corporation. All rights reserved.
/out:test_gcstl.exe
test_gcstl.obj
C:\spring2007\STL\gcstl>test_gcstl
abc bac bca
C:\spring2007\STL\gcstl>
-----------------------------------------------------
I used the old syntax option since that was also flagged as an error due to the __gc keyword which I guess is no longer used. I know it is hard to keep up with MS, but wondering if you have upgraded gcstl.h or will? Thanks, Dave
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Hi Dave.
In short, nothing is wrong with my code - the warning is wrong. std::copy is a perfectly valid standard function, and Microsoft has no business deprecating it - only the C++ Standard Comitee has that power. Authors of most other libraries take the same stand as I do - for instance, this is from the Boost[^] home page (scroll down to the Supported Compilers section):
Note: Boost does not support the non-standard "Safe" C++ Library shipping with Visual C++ 8.0, which may result in many spurious warnings from Boost headers and other standards-conforming C++ code. To suppress these warnings, define the macro _SCL_SECURE_NO_DEPRECATE
Best regards.
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#if defined(_MSC_VER) && _MSC_VER >= 1400
#pragma warning(push)
#pragma warning(disable:4996)
#endif
/* your stuff */
#if defined(_MSC_VER) && _MSC_VER >= 1400
#pragma warning(pop)
#endif
Thank you for your reply. I added this wrapper around your code to get rid of the other similar warnings, and it works fine! I like the idea very much.
-Dave
p.s.
cl /clr:oldSyntax /wd4996 test2_gcstl.cpp
These compiler options also work without adding the pragmas, but will I have to use "oldSyntax"? ...or is there a way to update your code to "new" syntax (whatever that is!)
-- modified at 11:21 Sunday 6th May, 2007
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ddtopham wrote: These compiler options also work without adding the pragmas, but will I have to use "oldSyntax"? ...or is there a way to update your code to "new" syntax (whatever that is!)
The new syntax is now called C++/CLI. Apparently there is some sort of converter to automatically convert the "old" Managed C++ syntax to the new one. Also, there is an STL implementation geared towards this new syntax - STL/CLR[^] which makes my gc wrappers pretty much obsolete, so if you want you can check it out as well.
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It is no secret that I am not very impressed with C#. I have worked with it because at one point it was declared a standard language in the company I work for, but I never really enjoyed it. Version 2.0 that is expected to appear in November is an improvement, but still nothing that would tempt me to switch to C# as my primary programming language.
However, I have seen the proposals for C# 3.0, and now I begin to wonder. So far, the new features include:
- type inference[^] for local variables;
- lambda expressions[^];
- anonymous types[^];
- object and collection initializers;
- query expressions;
C# 3.0 looks like a hybrid between an object and a functional language, almost like OCaml. To be honest I never expected C# team to be that brave in introducing new features, especially given the profile of a typical C# developer. It still does not mean I would take it by default for my new projects when I have a chance to choose: lack of performance and the fact that it runs in a managed environment still turn me off; however, just for the curiosity, I might take a good look into it.
My programming blahblahblah blog. If you ever find anything useful here, please let me know to remove it.
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Nevermind, Happy Birthday .
"I am a lair" Is this statement true or false ?
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So, I downloaded Boost 1.33, built it with BJam, and checked it in our VSS database. Having finished the whole exercise much sooner than originally planned, I decided to play a little bit with Boost Thread library. So I ran a simple test:
#include <vld.h>
#include "boost/thread.hpp"
#include <iostream>
void threadFunc ()
{
std::cout << "Hello, thread!";
}
int main()
{
boost::thread th(threadFunc);
th.join();
}
Note the vld.h header. I got into habbit of using the excellent Visual Leak Detector[^] by Dan Moulding, and sometimes I just include it even in the most trivial samples like the one above.
Surprise! The output from VLD:
WARNING: Visual Leak Detector detected memory leaks!
---------- Block 137 at 0x00328DE8: 24 bytes ----------
Call Stack:
c:\myprojects\libraries\boost\v1.33\libs\thread\src\mutex.inl (55): `anonymous namespace'::new_critical_section
c:\myprojects\libraries\boost\v1.33\libs\thread\src\mutex.cpp (48): boost::mutex::mutex
c:\myprojects\libraries\boost\v1.33\libs\thread\src\tss_hooks.cpp (29): `anonymous namespace'::init_threadmon_mutex
c:\myprojects\libraries\boost\v1.33\libs\thread\src\once.cpp (174): boost::call_once
c:\myprojects\libraries\boost\v1.33\libs\thread\src\tss_hooks.cpp (150): on_thread_exit
c:\myprojects\libraries\boost\v1.33\libs\thread\src\thread.cpp (117): thread_proxy
f:\vs70builds\3077\vc\crtbld\crt\src\threadex.c (241): _threadstartex
0x7C80B50B (File and line number not available): GetModuleFileNameA
Data:
A0 3F 14 00 FF FF FF FF 00 00 00 00 00 00 00 00 .?...... ........
00 00 00 00 00 00 00 00 ........ ........
---------- Block 136 at 0x00328AB0: 8 bytes ----------
Call Stack:
c:\myprojects\libraries\boost\v1.33\libs\thread\src\tss_hooks.cpp (29): `anonymous namespace'::init_threadmon_mutex
c:\myprojects\libraries\boost\v1.33\libs\thread\src\once.cpp (174): boost::call_once
c:\myprojects\libraries\boost\v1.33\libs\thread\src\tss_hooks.cpp (150): on_thread_exit
c:\myprojects\libraries\boost\v1.33\libs\thread\src\thread.cpp (117): thread_proxy
f:\vs70builds\3077\vc\crtbld\crt\src\threadex.c (241): _threadstartex
0x7C80B50B (File and line number not available): GetModuleFileNameA
Data:
E8 8D 32 00 01 CD CD CD ..2..... ........
Visual Leak Detector detected 2 memory leaks.
'cpptest.exe': Unloaded 'C:\WINDOWS\system32\dbghelp.dll'
'cpptest.exe': Unloaded 'C:\WINDOWS\system32\version.dll'
What happened here? Let's concentrate on the second one, from tss_hooks.cpp. The function from which the leak is reported looks like this:
void init_threadmon_mutex(void)
{
threadmon_mutex = new boost::mutex;
if (!threadmon_mutex)
throw boost::thread_resource_error();
}
So, the mutex object is created, but apperently never destroyed. Why?
If we look again at the call stack reported by VLD, we'll notice that function init_threadmon_mutex was called by boost::call_once , which in effect means we have a singleton here: threadmon_mutex can be created only once. Therefore, we don't really have a leak here: an object is created on the heap and never destroyed (more precisely, it gets destroyed when the process ends), but that's it. The problem with memory leaks is really repeatingly allocating memory that never gets released, and thus ending up with a crash; with Boost Thread library it can't happen - we can't create threadmon_mutex multiple times, it is a singleton. It is really a "memory drop", not a memory leak.
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Cool, i like your articles very much, i was looking for something like VLD so i will give it a try, thanks!
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A week ago or so, I noticed the new look of Boost[^] website. But more important, there is a new release with 5 new libraries and many updates for existing ones. This will be the first time I actually build Boost libraries - until now it was handled by a co-worker of mine who has left the company several months ago. Time to learn BJam[^] I guess
My programming blahblahblah blog. If you ever find anything useful here, please let me know to remove it.
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I ran into this book[^] in a bookstore. Generally, I dislike hype very much, and the title of this book is really "Hype to Hype", but I still decided to skim it. The things I expected to find were "how to apply 50 design patterns to write Hello World in Java".
What a surprise! In the very first chapter, author mentions the two most common errors in software design: overengineering and underengineering, and describes how he learned to avoid the first pitfall. Against my expectations, he does his best to warn readers of "patterns panacea" and "pattern happy" programmers. Instead, he advises the use of test driven development, and refactoring to patterns only when a real need justifies it.
I have suffered from both underengineered and overengineered design in my career, but it is the later that actually makes me angry more than the former: I don't want to waste my time learning someone's bloated frameworks that serve no real life purpose, and constrain me in solving real life problems. This kind of behavior is mostly typical of Java culture, which I don't belong to, but recently I have seen the same trend among C# developers, although to a lesser extent: everybody designs their own plug-in frameworks, their own XAML's, their own "enterprise frameworks", and complicate the design of their applications without any real need.
Does anybody remember the "KISS" principle any more? It seems that Joshua Kerievsky does, inspite of the title of his book.
My programming blahblahblah blog. If you ever find anything useful here, please let me know to remove it.
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One of the things I generally liked about Managed C++ (as opposed to i.e. C#) is the support for private virtual functions[^]. Ie. the following code will compile and run fine with MC++:
__gc class Base {
virtual void SomeVirtualFunction()
{Console::WriteLine(S"Base");}
public:
void SomeAccessibleFunction()
{SomeVirtualFunction();}
};
__gc class Derived : public Base {
virtual void SomeVirtualFunction()
{Console::WriteLine(S"Derived");}
};
int _tmain()
{
Base* handle = new Derived();
handle->SomeAccessibleFunction();
return 0;
}
However, take a look at the equivalent C++/CLI (Beta 2) code:
ref class Base {
virtual void SomeVirtualFunction()
{Console::WriteLine(L"Base");}
public:
void SomeAccessibleFunction()
{SomeVirtualFunction();}
};
ref class Derived : public Base {
virtual void SomeVirtualFunction() override
{Console::WriteLine(L"Derived");}
};
int main()
{
Base^ handle = gcnew Derived();
handle->SomeAccessibleFunction();
return 0;
}
(Note the override keyword in the derived class)
This program will compile, but with warnings like:
warning C4486: 'Base::SomeVirtualFunction' :
a private virtual method of a ref class or value class should be marked
'sealed'
However, when the program is run, an exception is thrown:
An unhandled exception of type 'System.TypeLoadException' occurred in
Virtual.exe
Additional information: Method 'SomeVirtualFunction' on type 'Derived'
from assembly 'Virtual, Version=1.0.1999.26811, Culture=neutral,
PublicKeyToken=null' is overriding a method that is not visible from
that assembly.
When comparing the IL generated by the two versions of Managed C++, I found out that C++/CLI adds an attribute strict to the declaration of virtual functions, and that caused this exception at run time.
The explanation came from Microsoft program managers Ronald Laeremans and Brandon Bray: Allowing private virtual functions is a security breach in managed (but not in unmanaged!!!)code, and that's why all Microsoft complers now emit strict .
Take a look at the complete thread here[^]
My programming blahblahblah blog. If you ever find anything useful here, please let me know to remove it.
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If you have ever thought dispose pattern was simple, read this[^] and you will definitelly change your mind
I just hope C++/CLI will automate this once it is finished.
My programming blahblahblah blog. If you ever find anything useful here, please let me know to remove it.
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wow, i wasnt expecting such a heavy read... It was well worth it though. Thanks
ade me;
while(myKitchen.beerInFridge()) {
me.watchTV();
me.consumeBeer(myKitchen.getBeerCan());
}
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Scary, ha?
The good news is that in C++/CLI you'll just need to write a destructor, and the compiler will take care of the rest.
My programming blahblahblah blog. If you ever find anything useful here, please let me know to remove it.
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I guess I was sleepy when I tried this (Windows Forms C#) code:
private void FillList()
{
System.IO.DirectoryInfo di = new System.IO.DirectoryInfo (lblPath.Text);
System.IO.FileSystemInfo[] files = di.GetFileSystemInfos();
lstFiles.ObjectCollection = files;
}
The last line is obviously a mistake, but the error that was reported by compiler could easily make somebody reinstall Visual Studio:
Performing main compilation...
error CS0583: Internal Compiler Error (0xc0000005 at address 535DB559): likely culprit is 'BIND'.
An internal error has occurred in the compiler. To work around this problem, try simplifying or changing the program near the locations listed below. Locations at the top of the list are closer to the point at which the internal error occurred.
c:\documents and settings\ntrifunovic\my documents\changemanagement\defecttrackingtovi\defecttrackingconverter\mainform.cs(30,4): error CS0585: Internal Compiler Error: stage 'BIND'
c:\documents and settings\ntrifunovic\my documents\changemanagement\defecttrackingtovi\defecttrackingconverter\mainform.cs(26,16): error CS0584: Internal Compiler Error: stage 'BIND' symbol 'DefectTrackingConverter.MainForm.FillList()'
c:\documents and settings\ntrifunovic\my documents\changemanagement\defecttrackingtovi\defecttrackingconverter\mainform.cs(26,16): error CS0584: Internal Compiler Error: stage 'COMPILE' symbol 'DefectTrackingConverter.MainForm.FillList()'
c:\documents and settings\ntrifunovic\my documents\changemanagement\defecttrackingtovi\defecttrackingconverter\mainform.cs(26,16): error CS0584: Internal Compiler Error: stage 'COMPILE' symbol 'DefectTrackingConverter.MainForm.FillList()'
c:\documents and settings\ntrifunovic\my documents\changemanagement\defecttrackingtovi\defecttrackingconverter\mainform.cs(26,16): error CS0584: Internal Compiler Error: stage 'COMPILE' symbol 'DefectTrackingConverter.MainForm.FillList()'
c:\documents and settings\ntrifunovic\my documents\changemanagement\defecttrackingtovi\defecttrackingconverter\mainform.cs(13,15): error CS0584: Internal Compiler Error: stage 'COMPILE' symbol 'DefectTrackingConverter.MainForm'
c:\documents and settings\ntrifunovic\my documents\changemanagement\defecttrackingtovi\defecttrackingconverter\mainform.cs(8,11): error CS0584: Internal Compiler Error: stage 'COMPILE' symbol 'DefectTrackingConverter'
c:\documents and settings\ntrifunovic\my documents\changemanagement\defecttrackingtovi\defecttrackingconverter\mainform.cs(1,1): error CS0584: Internal Compiler Error: stage 'COMPILE' symbol ''
C:\Documents and Settings\ntrifunovic\My Documents\ChangeManagement\DefectTrackingToVI\DefectTrackingConverter\MainForm.cs: error CS0586: Internal Compiler Error: stage 'COMPILE'
error CS0587: Internal Compiler Error: stage 'COMPILE'
error CS0587: Internal Compiler Error: stage 'BEGIN'
error CS0583: Internal Compiler Error (0xc0000005 at address 536250C6): likely culprit is 'BIND'.
An internal error has occurred in the compiler. To work around this problem, try simplifying or changing the program near the locations listed below. Locations at the top of the list are closer to the point at which the internal error occurred.
c:\documents and settings\ntrifunovic\my documents\changemanagement\defecttrackingtovi\defecttrackingconverter\mainform.cs(26,16): error CS0584: Internal Compiler Error: stage 'BIND' symbol 'DefectTrackingConverter.MainForm.FillList()'
c:\documents and settings\ntrifunovic\my documents\changemanagement\defecttrackingtovi\defecttrackingconverter\mainform.cs(26,16): error CS0584: Internal Compiler Error: stage 'COMPILE' symbol 'DefectTrackingConverter.MainForm.FillList()'
c:\documents and settings\ntrifunovic\my documents\changemanagement\defecttrackingtovi\defecttrackingconverter\mainform.cs(26,16): error CS0584: Internal Compiler Error: stage 'COMPILE' symbol 'DefectTrackingConverter.MainForm.FillList()'
c:\documents and settings\ntrifunovic\my documents\changemanagement\defecttrackingtovi\defecttrackingconverter\mainform.cs(26,16): error CS0584: Internal Compiler Error: stage 'COMPILE' symbol 'DefectTrackingConverter.MainForm.FillList()'
c:\documents and settings\ntrifunovic\my documents\changemanagement\defecttrackingtovi\defecttrackingconverter\mainform.cs(13,15): error CS0584: Internal Compiler Error: stage 'COMPILE' symbol 'DefectTrackingConverter.MainForm'
c:\documents and settings\ntrifunovic\my documents\changemanagement\defecttrackingtovi\defecttrackingconverter\mainform.cs(8,11): error CS0584: Internal Compiler Error: stage 'COMPILE' symbol 'DefectTrackingConverter'
c:\documents and settings\ntrifunovic\my documents\changemanagement\defecttrackingtovi\defecttrackingconverter\mainform.cs(1,1): error CS0584: Internal Compiler Error: stage 'COMPILE' symbol ''
C:\Documents and Settings\ntrifunovic\My Documents\ChangeManagement\DefectTrackingToVI\DefectTrackingConverter\MainForm.cs: error CS0586: Internal Compiler Error: stage 'COMPILE'
error CS0587: Internal Compiler Error: stage 'COMPILE'
error CS0587: Internal Compiler Error: stage 'BEGIN'
Build complete -- 23 errors, 0 warnings
My favorite part is this:
An internal error has occurred in the compiler. To work around this problem, try simplifying or changing the program near the locations listed below. Locations at the top of the list are closer to the point at which the internal error occurred.
Just "simplify" the program, and everything should be fine
My programming blahblahblah blog. If you ever find anything useful here, please let me know to remove it.
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If you ever use the Visual Studio Add-in wizard to generate a skeleton for a VS add-in, pay attention to this piece of code:
catch(System.Exception e)
{
}
Yeah, I know, error handling is not easy, but it can't be replaced by humor.
My programming blahblahblah blog. If you ever find anything useful here, please let me know to remove it.
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I decided to play with F#[^], an ML dialect that maps to .NET framework. Reasons? I've never really learned any functional language, and F# looks like an interesting first step. I downloaded the installer from the MS site, and although there were some glitches, I installed it successfuly. It even integrates into VS, although it is far from perfect. Documentation is very poor, so I am mostly using OCaml tutorials for the time being. Here is a simple program in F#:
(* A sample function *)
let avg a b =
let sum = a +. b in
sum /. 2.;;
(* this is what we used to call main *)
let _ =
System.Console.WriteLine(avg 4. 6.);;
Sexy, ah? One thing I hate about C-like languages is curly braces all over the place, and look how cute it looks without them. I might just get to like F#...
My programming blahblahblah blog. If you ever find anything useful here, please let me know to remove it.
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All those lets in there remind me of GWBASIC
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