HI,
I am normally a C programmer.
I do regularly debug C programs on unix environment using tools like gdb,dbx.
i have never done debugging of big applications of C++.
Is that much different from how we debug in C.
theoretically i am quite good in C++ but have never got a chance to debug C++ programs.
I am also not sure about what kind of technical problems we face in c++ which will lead a developer to switch on the debugger for finding out the problem.
what are the common issues we face in C++ which will make debugger to be started
what are the challenges that a c programmer might face while debugging a C++ program?
Is it difficult and complex when compared to C?
It is basically the same.
Just remember when setting break points manually you need to fully qualify the method name with both the namespace(s) and class (As a resul i someti es find it easier to use line numbers to define break points)
Don't forget that calls to destructors are invisible in the source, but you can still step into them at the end of a block.
A few minor differences:
When typing a full-qualified symbol such as foo::bar::fum(args) in the gdb shell you have to start with a single quote for gdb to recognize it and calculate completions.
As others have said, library templates expose their internals in the debugger. You can poke around in std::vector pretty easily, but poking through std::map may not be a wise way to spend your time.
The aggressive and abundant inlining common in C++ programs can make a single line of code have seemingly endless steps. Things like shared_ptr can be particularly annoying because every access to the pointer expands inline to the template internals. You never really get to used it.
If you've got a ton of overloaded symbol names, selecting which one you want from the readline completion can be unpleasant. (Which "foo" did you want? All of them? Just these two?)
GDB can be used to debug C++ as well, so if you have an understanding of how C++ works (and understand problems that can stem from the object-oriented side of things), then you shouldn't have all that much trouble (at least, not much more than you would debugging a C program). I think...
Quite a few issues really, but it also depends on the debugger you are using, its versioning etc:
Accessing individual members of templatized class is not easy
Exception handling is a problem -- i have seen debuggers doing a better job with setjmp/longjmp
Setting breakpoints with something like obj1 == obj2, where these are not POD types may not work
The good thing that I like about debuggers is that to access private/protected class members I don't have to call get routines; just [obj-name].[var-name] is good enough.
Arpan
GDB has had a rocky past with regard to debugging c++. For a while it couldn't efficiently break inside constructors/destructors.
Also stl container were netoriously difficult to inspect in gdb. std::string was painful but generally workable. std::map was so difficult, that I generally added print statements unless there was no other way.
The constructor/destructor problem has been fixed for a few years.
The stl support got fixed in gdb 7.0.
You might still have issues with boost's libraries. I at time had difficulty getting gdb to give me asses to the contents of a shared_ptr.
So I guess debugging your own C++ isn't really that difficult, it's debugging 3rd party classes and template code that could be a problem.
C++ objects might be sometimes harder to analyze. Also as data is sometimes nested in several classes (across several layers) it might take some time to "unfold" it (as already said by others in this thread). Its hard to generally say so, as it depends very much on C++ features used and programming style and complexity of the problem to analyze (actually that is language independent).
IMO: if someone finds himselfself in the need to debug very often he should reconsider his programming style.
Usually for me it is all about error handling at the end. If a program behaves unexpected your error logs should indicate enough information to reconstruct what happened at any stage.
This also gives you the benefit that you can "debug" problems offline later once your program gets shipped to end users.
Related
I encountered this issue a dozen, if not a million times already: I compile a c++ program on visual studio and get a dozen, if not a million warnings and/or errors suggesting that I am doing something very dangerous and that there is no way my compiler will let me do that. the warnings/errors tell me that I am using a deprecated function and that I should consider using some other safer function that may or may not do the same thing as this one, but I have no idea what this one does in the first place since I did not write it.
After some research (I do it everytime, I am not a quick learner) I find out I am not the first one facing this particular problem, and I can coerce my compiler to work with this program with the proper macro definition (for the future readers who don't care about my question but want to compile their program, you have to define _CRT_SECURE_NO_DEPRECATE, don't you ever dare following visual studio's advice and using the allegedly safe function).
I have often read in the manual or on this very website, along with the answer, the fact that I should not do that if I don't know precisely what I am doing.
I must confess: I have no idea what I am doing, and I would be very grateful if someone would accept to explain it to me.
So here are my questions:
What are those functions that are unsafe? Why do they exist in the first place?
What is unsafe about them?
Why are they so often found in perfectly honourable libraries?
I have come to the understanding that there is no safe and portable alternative to those functions: why is it so? How about we have some people think about it and try to define a way to do it, and everyone would accept to do it that way, and we would call it standard maybe?
To tackle your questions in order:
They exist in the first place because the standard wrote them in such a way. Standards authors are human so don't think of everything and this left some security weaknesses in the C API. You can find a list of these deprecated functions at http://msdn.microsoft.com/en-us/library/ms235384.aspx.
Many of the functions are unsafe as they allow such things as buffer overruns to occur but other security vulnerabilities may be exposed depending on the function.
Honourable libraries generally try for some cross platform compatibility so I suspect will try to stick to stand C rather than using compiler specific functions and extensions.
The "perfect" standard will probably never exist as in my first point :) Some of the C API problems can be avoided using C++ but that's a big hammer to crack a small nut and brings security vulnerabilities of its own.
I know that E&C is a controversial subject and some say that it encourages a wrong approach to debugging, but still - I think we can agree that there are numerous cases when it is clearly useful - experimenting with different values of some constants, redesigning GUI parameters on-the-fly to find a good look... You name it.
My question is: Are we ever going to have E&C on GDB? I understand that it is a platform-specific feature and needs some serious cooperation with the compiler, the debugger and the OS (MSVC has this one easy as the compiler and debugger always come in one package), but... It still should be doable. I've even heard something about Apple having it implemented in their version of GCC [citation needed]. And I'd say it is indeed feasible.
Knowing all the hype about MSVC's E&C (my experience says it's the first thing MSVC users mention when asked "why not switch to Eclipse and gcc/gdb"), I'm seriously surprised that after quite some years GCC/GDB still doesn't have such feature. Are there any good reasons for that? Is someone working on it as we speak?
It is a surprisingly non-trivial amount of work, encompassing many design decisions and feature tradeoffs. Consider: you are debugging. The debugee is suspended. Its image in memory contains the object code of the source, and the binary layout of objects, the heap, the stacks. The debugger is inspecting its memory image. It has loaded debug information about the symbols, types, address mappings, pc (ip) to source correspondences. It displays the call stack, data values.
Now you want to allow a particular set of possible edits to the code and/or data, without stopping the debuggee and restarting. The simplest might be to change one line of code to another. Perhaps you recompile that file or just that function or just that line. Now you have to patch the debuggee image to execute that new line of code the next time you step over it or otherwise run through it. How does that work under the hood? What happens if the code is larger than the line of code it replaced? How does it interact with compiler optimizations? Perhaps you can only do this on a specially compiled for EnC debugging target. Perhaps you will constrain possible sites it is legal to EnC. Consider: what happens if you edit a line of code in a function suspended down in the call stack. When the code returns there does it run the original version of the function or the version with your line changed? If the original version, where does that source come from?
Can you add or remove locals? What does that do to the call stack of suspended frames? Of the current function?
Can you change function signatures? Add fields to / remove fields from objects? What about existing instances? What about pending destructors or finalizers? Etc.
There are many, many functionality details to attend to to make any kind of usuable EnC work. Then there are many cross-tools integration issues necessary to provide the infrastructure to power EnC. In particular, it helps to have some kind of repository of debug information that can make available the before- and after-edit debug information and object code to the debugger. For C++, the incrementally updatable debug information in PDBs helps. Incremental linking may help too.
Looking from the MS ecosystem over into the GCC ecosystem, it is easy to imagine the complexity and integration issues across GDB/GCC/binutils, the myriad of targets, some needed EnC specific target abstractions, and the "nice to have but inessential" nature of EnC, are why it has not appeared yet in GDB/GCC.
Happy hacking!
(p.s. It is instructive and inspiring to look at what the Smalltalk-80 interactive programming environment could do. In St80 there was no concept of "restart" -- the image and its object memory were always live, if you edited any aspect of a class you still had to keep running. In such environments object versioning was not a hypothetical.)
I'm not familiar with MSVC's E&C, but GDB has some of the things you've mentioned:
http://sourceware.org/gdb/current/onlinedocs/gdb/Altering.html#Altering
17. Altering Execution
Once you think you have found an error in your program, you might want to find out for certain whether correcting the apparent error would lead to correct results in the rest of the run. You can find the answer by experiment, using the gdb features for altering execution of the program.
For example, you can store new values into variables or memory locations, give your program a signal, restart it at a different address, or even return prematurely from a function.
Assignment: Assignment to variables
Jumping: Continuing at a different address
Signaling: Giving your program a signal
Returning: Returning from a function
Calling: Calling your program's functions
Patching: Patching your program
Compiling and Injecting Code: Compiling and injecting code in GDB
This is a pretty good reference to the old Apple implementation of "fix and continue". It also references other working implementations.
http://sources.redhat.com/ml/gdb/2003-06/msg00500.html
Here is a snippet:
Fix and continue is a feature implemented by many other debuggers,
which we added to our gdb for this release. Sun Workshop, SGI ProDev
WorkShop, Microsoft's Visual Studio, HP's wdb, and Sun's Hotspot Java
VM all provide this feature in one way or another. I based our
implementation on the HP wdb Fix and Continue feature, which they
added a few years back. Although my final implementation follows the
general outlines of the approach they took, there is almost no shared
code between them. Some of this is because of the architectual
differences (both the processor and the ABI), but even more of it is
due to implementation design differences.
Note that this capability may have been removed in a later version of their toolchain.
UPDATE: Dec-21-2012
There is a GDB Roadmap PDF presentation that includes a slide describing "Fix and Continue" among other bullet points. The presentation is dated July-9-2012 so maybe there is hope to have this added at some point. The presentation was part of the GNU Tools Cauldron 2012.
Also, I get it that adding E&C to GDB or anywhere in Linux land is a tough chore with all the different components.
But I don't see E&C as controversial. I remember using it in VB5 and VB6 and it was probably there before that. Also it's been in Office VBA since way back. And it's been in Visual Studio since VS2005. VS2003 was the only one that didn't have it and I remember devs howling about it. They intended to add it back anyway and they did with VS2005 and it's been there since. It works with C#, VB, and also C and C++. It's been in MS core tools for 20+ years, almost continuous (counting VB when it was standalone), and subtracting VS2003. But you could still say they had it in Office VBA during the VS2003 period ;)
And Jetbrains recently added it too their C# tool Rider. They bragged about it (rightly so imo) in their Rider blog.
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While C++ Standards Committee works hard to define its intricate but powerful features and maintain its backward compatibility with C, in my personal experience I've found many aspects of programming with C++ cumbersome due to lack of tools.
For example, I recently tried to refactor some C++ code, replacing many shared_ptr by T& to remove pointer usages where not needed within a large library. I had to perform almost the whole refactoring manually as none of the refactoring tools out there would help me do this safely.
Dealing with STL data structures using the debugger is like raking out the phone number of a stranger when she disagrees.
In your experience, what essential developer tools are lacking in C++?
My dream tool would be a compile-time template debugger. Something that'd let me interactively step through template instantiations and examine the types as they get instantiated, just like the regular debugger does at runtime.
In your experience, what essential developer tools are lacking in C++?
Code completion. Seriously. Refactoring is a nice-to-have feature but I think code completion is much more fundamental and more important for API discoverabilty and usabilty.
Basically, tools that require any undestanding of C++ code suck.
Code generation of class methods. When I type in the declaration you should be able to figure out the definition. And while I'm on the topic can we fix "goto declaration / goto definition" always going to the declaration?
Refactoring. Yes I know it's formally impossible because of the pre-processor - but the compiler could still do a better job of a search and replace on a variable name than I can maually. You could also syntax highlight local, members and paramaters while your at it.
Lint. So the variable I just defined shadows a higher one? C would have told me that in 1979, but c++ in 2009 apparently prefers me to find out on my own.
Some decent error messages. If I promise never to define a class with the same name inside the method of a class - do you promise to tell me about a missing "}". In fact can the compiler have some knowledge of history - so if I added an unbalanced "{" or "(" to a previously working file could we consider mentioning this in the message?
Can the STL error messages please (sorry to quote another comment) not look like you read "/dev/random", stuck "!/bin/perl" in front and then ran the tax code through the result?
How about some warnings for useful things? "Integer used as bool performance warning" is not useful, it doesn't make any performance difference, I don't have a choice - it's what the library does, and you have already told me 50 times.
But if I miss a ";" from the end of a class declaration or a "}" from the end of a method definition you don't warn me - you go out of your way to find the least likely (but theoretically) correct way to parse the result.
It's like the built in spell checker in this browser which happily accepts me misspelling wether (because that spelling is an archaic term for a castrated male goat! How many times do I write about soprano herbivores?)
How about spell checking? 40 years ago mainframe Fortran compilers had spell checking so if misspelled "WRITE" you didn't come back the next day to a pile of cards and a snotty error message. You got a warning that "WRIET" had been changed to WRITE in line X. Now the compiler happily continues and spends 10mins building some massive browse file and debugger output before telling you that you misspelled prinft 10,000 lines ago.
ps. Yes a lot of these only apply to Visual C++.
pps. Yes they are coming with my medication now.
If talking about MS Visual Studio C++, Visual Assist is a very handy tool for code completition, some refactorings - e.g. rename all/selected references, find/goto declaration, but I still miss the richness of Java IDEs like JBuilder or IntelliJ.
What I still miss, is a semantic diff tool - you know, one which does not compare the two files line-by-line, but statements/expressions. What I've found on the internet are only some abandoned tries - if you know one, please write in comment
The main problem with C++ is that it is hard to parse. That's why there are so very few tools out there that work on source code. (And that's also why we're stuck with some of the most horrific error messages in the history of compilers.) The result is, that, with very few exceptions (I only know doxygen and Visual Assist), it's down to the actual compiler to support everything needed to assist us writing and massaging the code. With compilers traditionally being rather streamlined command line tools, that's a very weak foundation to build rich editor support on.
For about ten years now, I'm working with VS. meanwhile, its code completion is almost usable. (Yes, I'm working on dual core machines. I wouldn't have said this otherwise, wouldn't I?) If you use Visual Assist, code completion is actually quite good. Both VS itself and VA come with some basic refactoring nowadays. That, too, is almost usable for the few things it aims for (even though it's still notably less so than code completion). Of course, >15 years of refactoring with search & replace being the only tool in the box, my demands are probably much too deteriorated compared to other languages, so this might not mean much.
However, what I am really lacking is still: Fully standard conforming compilers and standard library implementations on all platforms my code is ported to. And I'm saying this >10 years after the release of the last standard and about a year before the release of the next one! (Which just adds this: C++1x being widely adopted by 2011.)
Once these are solved, there's a few things that keep being mentioned now and then, but which vendors, still fighting with compliance to a >10 year old standard (or, as is actually the case with some features, having even given up on it), never got around to actually tackle:
usable, sensible, comprehensible compiler messages (como is actually pretty good, but that's only if you compare it to other C++ compilers); a linker that doesn't just throw up its hands and says "something's wrong, I can't continue" (if you have taught C++ as a first language, you'll know what I mean); concepts ('nuff said)
an IO stream implementation that doesn't throw away all the compile-time advantages which overloading operator<<() gives us by resorting to calling the run-time-parsing printf() under the hood (Dietmar Kühl once set out to do this, unfortunately his implementation died without the techniques becoming widespread)
STL implementations on all platforms that give rich debugging support (Dinkumware is already pretty good in that)
standard library implementations on all platforms that use every trick in the book to give us stricter checking at compile-time and run-time and more performance (wnhatever happened to yasli?)
the ability to debug template meta programs (yes, jalf already mentioned this, but it cannot be said too often)
a compiler that renders tools like lint useless (no need to fear, lint vendors, that's just wishful thinking)
If all these and a lot of others that I have forgotten to mention (feel free to add) are solved, it would be nice to get refactoring support that almost plays in the same league as, say, Java or C#. But only then.
A compiler which tries to optimize the compilation model.
Rather than naively include headers as needed, parsing them again in every compilation unit, why not parse the headers once first, build complete syntax trees for them (which would have to include preprocessor directives, since we don't yet know which macros are defined), and then simply run through that syntax tree whenever the header is included, applying the known #defines to prune it.
It could even be be used as a replacement for precompiled headers, so every header could be precompiled individually, just by dumping this syntax tree to the disk. We wouldn't need one single monolithic and error-prone precompiled header, and would get finer granularity on rebuilds, rebuilding as little as possible even if a header is modified.
Like my other suggestions, this would be a lot of work to implement, but I can't see any fundamental problems rendering it impossible.
It seems like it could dramatically speed up compile-times, pretty much rendering it linear in the number of header files, rather than in the number of #includes.
A fast and reliable indexer. Most of the fancy features come after this.
A common tool to enforce coding standards.
Take all the common standards and allow you to turn them on/off as appropriate for your project.
Currently just a bunch of perl scrips usullay has to supstitute.
I'm pretty happy with the state of C++ tools. The only thing I can think of is a default install of Boost in VS/gcc.
Refactoring, Refactoring, Refactoring. And compilation while typing. For refactorings I am missing at least half of what most modern Java IDEs can do. While Visual Assist X goes a long way, a lot of refactoring is missing. The task of writing C++ code is still pretty much that. Writing C++ code. The more the IDE supports high level refactoring the more it becomes construction, the more mallable the structure is the easier it will be to iterate over the structure and improve it. Pick up a demo version of Intellij and see what you are missing. These are just some that I remember from a couple of years ago.
Extract interface: taken a view classes with a common interface, move the common functions into an interface class (for C++ this would be an abstract base class) and derive the designated functions as abstract
Better extract method: mark a section of code and have the ide write a function that executes that code, constructing the correct parameters and return values
Know the type of each of the symbols that you are working with so that not only command completion can be correct for derived values e.g. symbol->... but also only offer functions that return the type that can be used in the current expression e.g. for
UiButton button = window->...
At the ... only insert functions that actually return a UiButton.
A tool all on it's own: Naming Conventions.
Intelligent Intellisense/Code Completion even for template-heavy code.
When you're inside a function template, of course the compiler can't say anything for sure about the template parameter (at least not without Concepts), but it should be able to make a lot of guesses and estimates. Depending on how the type is used in the function, it should be able to narrow the possible types down, in effect a kind of conservative ad-hoc Concepts. If one line in the function calls .Foo() on a template type, obviously a Foo member method must exist, and Intellisense should suggest it in the rest of the function as well.
It could even look at where the function is invoked from, and use that to determine at least one valid template parameter type, and simply offer Intellisense inside the function based on that.
If the function is called with a int as a template parameter, then obviously, use of int must be valid, and so the IDE could use that as a "sample type" inside the function and offer Intellisense suggestions based on that.
JavaScript just got Intellisense support in VS, which had to overcome a lot of similar problems, so it can be done. Of course, with C++'s level of complexity, it'd be a ridiculous amount of work. But it'd be a nice feature.
Debugging with gdb, any c++ code that uses STL/boost is still a nightmare. Anyone who has used gdb with STL knows this. For example, see sample runs of some debugging sessions in code here.
I am trying to reduce the pain by collecting tips. Can you please comment on the tips I have collected below (particularly which ones you have been using and any changes you would recommend on them) - I have listed the tips is decreasing order of technicality.
Is anyone using "Stanford GDB STL utils" and "UCF GDB utils"? Is there some such utils for boost data structures? The utils above do not seem to be usable recursively, for example for printing vector of a boost::shared_ptr in a legible manner within one command.
Write your .gdbinit file. Include, for example, C++ related beautifiers, listed at the bottom of UCF GDB utils.
Use checked/debug STL/Boost library, such as STLport.
Use logging (for example as described here)
Update: GDB has a new C++ branch.
Maybe not the sort of "tip" you were looking for, but I have to say that my experience after a few years of moving from C++ & STL to C++ & boost & STL is that I now spend a lot less time in GDB than I used to. I put this down to a number of things:
boost smart pointers (particularly "shared pointer", and the pointer containers when performance is needed). I can't remember the last time I had to write an explicit delete (delete is the "goto" of C++ IMHO). There goes a lot of GDB time tracking down invalid and leaking pointers.
boost is full of proven code for things you'd probably hack together an inferior version of otherwise. e.g boost::bimap is great for the common pattern of LRU caching logic. There goes another heap of GDB time.
Adopting unittesting. boost::test's AUTO macros mean it's an absolute doddle to set up test cases (easier than CppUnit). This catches lots of stuff long before it gets built into anything you'd have to attach a debugger to.
Related to that, tools like boost::bind make it easier to design-for-test. e.g algorithms can be more generic and less tied up with the types they operate on; this makes plugging them into test shims/proxies/mock objects etc easier (that and the fact that exposure to boost's template-tasticness will encourage you to "dare to template" things you'd never have considered before, yielding similar testing benefits).
boost::array. "C array" performance, with range checking in debug builds.
boost is full of great code you can't help but learn from
You might look at:
Inspecting standard container (std::map) contents with gdb
I think the easiest and most option is to use logging (well I actually use debug prints, but I think that's not a point). The biggest advantage is that you can inspect any type of data, many times per program execution and then search it with a text editor to look for interesting data. Note that this is very fast. The disadvantage is obvious, you must preselect the data which you want to log and places where to log. However, that is not such a serious issue, because you usually know where in the code bad things are happening (and if not, you just add sanity checks here and there and then, you will know).
Checked/debug libraries are good, but they are better as a testing tool (eg. run it and see if I'm doing anything wrong), and not as good at debugging a specific issue. They can't detect a flaw in user code.
Otherwise, I use plain GDB. It is not that bad as it sounds, although it might be if you are scared by "print x" printing a screenful of junk. But, if you have debugging information, things like printing a member of a std::vector work and if anything fails, you still can inspect the raw memory by the x command. But if I know what I'm looking for, I use option 1 - logging.
Note that the "difficult to inspect" structures are not only STL/Boost, but also from other libraries, like Qt/KDE.
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We are producing a portable code (win+macOs) and we are looking at how to make the code more rubust as it crashes every so often... (overflows or bad initializations usually) :-(
I was reading that Google Chrome uses a process for every tab so if something goes wrong then the program does not crash compleatelly, only that tab. I think that is quite neat, so i might give it a go!
So i was wondering if someone has some tips, help, reading list, comment, or something that can help me build more rubust c++ code (portable is always better).
In the same topic i was also wondering if there is a portable library for processes (like boost)?
Well many Thanks.
I've developed on numerous multi-platform C++ apps (the largest being 1.5M lines of code and running on 7 platforms -- AIX, HP-UX PA-RISC, HP-UX Itanium, Solaris, Linux, Windows, OS X). You actually have two entirely different issues in your post.
Instability. Your code is not stable. Fix it.
Use unit tests to find logic problems before they kill you.
Use debuggers to find out what's causing the crashes if it's not obvious.
Use boost and similar libraries. In particular, the pointer types will help you avoid memory leaks.
Cross-platform coding.
Again, use libraries that are designed for this when possible. Particularly for any GUI bits.
Use standards (e.g. ANSI vs gcc/MSVC, POSIX threads vs Unix-specific thread models, etc) as much as possible, even if it requires a bit more work. Minimizing your platform specific code means less overall work, and fewer APIs to learn.
Isolate, isolate, isolate. Avoid in-line #ifdefs for different platforms as much as possible. Instead, stick platform specific code into its own header/source/class and use your build system and #includes to get the right code. This helps keep the code clean and readable.
Use the C99 integer types if at all possible instead of "long", "int", "short", etc -- otherwise it will bite you when you move from a 32-bit platform to a 64-bit one and longs suddenly change from 4 bytes to 8 bytes. And if that's ever written to the network/disk/etc then you'll run into incompatibility between platforms.
Personally, I'd stabilize the code first (without adding any more features) and then deal with the cross-platform issues, but that's up to you. Note that Visual Studio has an excellent debugger (the code base mentioned above was ported to Windows just for that reason).
The Chrome answer is more about failure mitigation and not about code quality. Doing what Chrome is doing is admitting defeat.
Better QA that is more than just programmer testing their own work.
Unit testing
Regression testing
Read up on best practices that other
companies use.
To be blunt, if your software is crashing often due to overflows and bad initializations, then you have a very basic programming quality problem that isn't going to be easily fixed. That sounds a hash and mean, that isn't my intent. My point is that the problem with the bad code has to be your primary concern (which I'm sure it is). Things like Chrome or liberal use to exception handling to catch program flaw are only distracting you from the real problem.
You don't mention what the target project is; having a process per-tab does not necessarily mean more "robust" code at all. You should aim to write solid code with tests regardless of portability - just read about writing good C++ code :)
As for the portability section, make sure you are testing on both platforms from day one and ensure that no new code is written until platform-specific problems are solved.
You really, really don't want to do what Chrome is doing, it requires a process manager which is probably WAY overkill for what you want.
You should investigate using smart pointers from Boost or another tool that will provide reference counting or garbage collection for C++.
Alternatively, if you are frequently crashing you might want to perhaps consider writing non-performance critical parts of your application in a scripting language that has C++ bindings.
Scott Meyers' Effective C++ and More Effective C++ are very good, and fun to read.
Steve McConnell's Code Complete is a favorite of many, including Jeff Atwood.
The Boost libraries are probably an excellent choice. One project where I work uses them. I've only used WIN32 threading myself.
I agree with Torlack.
Bad initialization or overflows are signs of poor quality code.
Google did it that way because sometimes, there was no way to control the code that was executed in a page (because of faulty plugins, etc.). So if you're using low quality plug ins (it happens), perhaps the Google solution will be good for you.
But a program without plugins that crashes often is just badly written, or very very complex, or very old (and missing a lot of maintenance time). You must stop the development, and investigate each and every crash. On Windows, compile the modules with PDBs (program databases), and each time it crashes, attach a debugger to it.
You must add internal tests, too. Avoid the pattern:
doSomethingBad(T * t)
{
if(t == NULL) return ;
// do the processing.
}
This is very bad design because the error is there, and you just avoid it, this time. But the next function without this guard will crash. Better to crash sooner to be nearer from the error.
Instead, on Windows (there must be a similar API on MacOS)
doSomethingBad(T * t)
{
if(t == NULL) ::DebugBreak() ; // it will call the debugger
// do the processing.
}
(don't use this code directly... Put it in a define to avoid delivering it to a client...)
You can choose the error API that suits you (exceptions, DebugBreak, assert, etc.), but use it to stop the moment the code knows something's wrong.
Avoid the C API whenever possible. Use C++ idioms (RAII, etc.) and libraries.
Etc..
P.S.: If you use exceptions (which is a good choice), don't hide them inside a catch. You'll only make your problem worse because the error is there, but the program will try to continue and will probably crash sometimes after, and corrupt anything it touches in the mean time.
You can always add exception handling to your program to catch these kinds of faults and ignore them (though the details are platform specific) ... but that is very much a two edged sword. Instead consider having the program catch the exceptions and create dump files for analysis.
If your program has behaved in an unexpected way, what do you know about your internal state? Maybe the routine/thread that crashed has corrupted some key data structure? Maybe if you catch the error and try to continue the user will save whatever they are working on and commit the corruption to disk?
Beside writing more stable code, here's one idea that answers your question.
Whether you are using processes or threads. You can write a small / simple watchdog program. Then your other programs register with that watchdog. If any process dies, or a thread dies, it can be restarted by the watchdog. Of course you'll want to put in some test to make sure you don't keep restarting the same buggy thread. ie: restart it 5 times, then after the 5th, shutdown the whole program and log to file / syslog.
Build your app with debug symbols, then either add an exception handler or configure Dr Watson to generate crash dumps (run drwtsn32.exe /i to install it as the debugger, without the /i to pop the config dialog). When your app crashes, you can inspect where it went wrong in windbg or visual studio by seeing a callstack and variables.
google for symbol server for more info.
Obviously you can use exception handling to make it more robust and use smart pointers, but fixing the bugs is best.
I would recommend that you compile up a linux version and run it under Valgrind.
Valgrind will track memory leaks, uninitialized memory reads and many other code problems. I highly recommend it.
After over 15 years of Windows development I recently wrote my first cross-platform C++ app (Windows/Linux). Here's how:
STL
Boost. In particular the filesystem and thread libraries.
A browser based UI. The app 'does' HTTP, with the UI consisting of XHTML/CSS/JavaScript (Ajax style). These resources are embedded in the server code and served to the browser when required.
Copious unit testing. Not quite TDD, but close. This actually changed the way I develop.
I used NetBeans C++ for the Linux build and had a full Linux port in no time at all.
Build it with the idea that the only way to quit is for the program to crash and that it can crash at any time. When you build it that way, crashing will never/almost never lose any data. I read an article about it a year or two ago. Sadly, I don't have a link to it.
Combine that with some sort of crash dump and have it email you it so you can fix the problem.