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  • remote function with pthread

    - by user311130
    Hi all, I wrote some code in c, using pthread (I configured the linker and compiler in eclipse IDE first). #include <pthread.h> #include "starter.h" #include "UI.h" Page* MM; Page* Disk; PCB* all_pcb_array; void* display_prompt(void *id){ printf("Hello111\n"); return NULL; } int main(int argc, char** argv) { printf("Hello\n"); pthread_t *thread = (pthread_t*) malloc (sizeof(pthread_t)); pthread_create(thread, NULL, display_prompt, NULL); printf("Hello\n"); return 1; } that works fine. However, when I move display_prompt to UI.h no "Hello111 " output is printed. anyone know how to solve that? Elad

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  • Using memory mapping in C for reading binary

    - by user1320912
    I am trying to read data from a binary file and process it.It is a very large file so I thought I would use memory mapping. I am trying to use memory mapping so I can read the file byte by byte. I am getting a few compiler errors while doing this. I am doing this on a linux platform #include <unistd.h> #include <sys/types.h> #include <sys/mman.h> int fd; char *data; fd = open("data.bin", O_RDONLY); pagesize = 4000; data = mmap((caddr_t)0, pagesize, PROT_READ, MAP_SHARED, fd, pagesize); The errors i get are : caddr not initialized, R_RDONLY not initialized, mmap has too few arguments. Could someone help me out ?

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  • Optional structural typing possibilty in C++ or anyother language?

    - by ambhai
    In C++ how to tell compiler that Ogre::Vector3 IS_SAME_AS SomeOtherLIB::Vector3 ? I feel that.. in languages like c++ which are not structural typed but there are cases when it makes sense. Normally as game developer when working with 4+ libraries that provide sort or their own Vector3 implementation. The code is littered with ToOgre, ToThis, ToThat conversion function. Thats a lot of Float3 copying around which should not happen on first place. Is in C++ or any other languages where we dont have to convert (copying) from one type to another which is essentially the samething. But any solution in C++ as most of the good gamedevs libs are for c/c++.

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  • What is the proper way to declare a specialization of a template for another template type?

    - by Head Geek
    The usual definition for a specialization of a template function is something like this: class Foo { [...] }; namespace std { template<> void swap(Foo& left, Foo& right) { [...] } } // namespace std But how do you properly define the specialization when the type it's specialized on is itself a template? Here's what I've got: template <size_t Bits> class fixed { [...] }; namespace std { template<size_t Bits> void swap(fixed<Bits>& left, fixed<Bits>& right) { [...] } } // namespace std Is this the right way to declare swap? It's supposed to be a specialization of the template function std::swap, but I can't tell whether the compiler is seeing it as such, or whether it thinks that it's an overload of it or something.

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  • Succinct code over verbose?

    - by WeNeedAnswers
    With C# becoming more and more declarative and becoming the new Swiss army knife of Programming. Is it better to be succinct thus reducing the actual code base, or long winded but verbose. Is there a performance issue with succinct or does being succinct improve performance because your putting more of your code in the hands of the compiler. (LINQ being an example when used correctly). I know that verbosity should override succinct where code would become less readable, but is this a good idea when your style could affect the performance.

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  • Returning NSNull from actionForLayer:forKey

    - by MrHen
    If I implement the CALayer delegate method actionForLayer:forKey I can return [NSNull null] to force the CALayer to not animate any changes. Unfortunately, [NSNull null] doesn't implement the CAAction delegate and XCode kicks out the following warning: warning: class 'NSNull' does not implement the 'CAAction' protocol Here is the method code: - (id<CAAction>)actionForLayer:(CALayer *)theLayer forKey:(NSString *)theKey { //This disables the animations when moving things around //Also, don't animate the selection box. It was doing weird things if(undoGroupStarted || theLayer == self.selectionBox) { return [NSNull null]; } else { return nil; } } Am I doing something wrong? Is returning [NSNull null] bad behavior? If so, what is another way to do what I am trying to do here? If not, how do I make the compiler happy?

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  • C++ overloading virtual = operator

    - by taz
    Hello, here is the code for my question: class ICommon { public: virtual ICommon& operator=(const ICommon & p)const=0; }; class CSpecial : public ICommon { public: CSpecial& operator=(const CSpecial & cs) { //custom operations return *this; } }; CSpecial obj; Basically: I want the interface ICommon to force it's descendants to implement = operator but don't want to have any typecasts in the implementation. The compiler says "can't instantiate an abstract class. Any help/advice will be appreciated.

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  • A feeling that I'm not that good developer

    - by Karim
    Hi, Im having a strange feeling, but let me first introduce myself as a software developer. I started to program when I was still a kid, I had about 10 or 11 years. I really enjoy my work and never get bored from it. It's amazing how somebody could be paid for what he really likes to do and would be doing it anyway even for free. WHen I first started to program, I was feeling proud of what I was doing, each application I built was for me a success and after 2-3 year I had a feeling that I'm a coding guru. It was a nice feeling ;-) But the more I was in the field, the more types of software I started to develop I was starting to have a feeling that I'm completely wrong in that I'm guru. I felt that I'm not even a mediocre developer. Each new field I start to work on is giving me this feeling. Like when I once developed a device driver for a client, I saw how much I need to learn about device drivers. When I developed a video filter for an application, I saw how much do I still need to learn about DirectShow, Color Spaces, and all the theory behind that. The worst thing was when I started to learn algorithms. It was several years ago. I knew then the basic structures and algorithms like the sorting, some types of trees, some hashtables, strings etc.. and when I really wanted to learn a group of structures I learned about 5-6 new types and saw that in fact even this small group has several hundred subtypes of structures. It's depressing how little time people have in their lives to learn all this stuff. I'm now a software developer with about 10 years of experience and I still feel that I'm not a proficient developer when I think about things that others do in the industry. Is this normal what I'm experiencing or is it a sign of a destructive excessive ambition? Thanks in advance for any comments.

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  • snprintf and Visual Studio 2010

    - by Andrew
    I'm unfortunate enough to be stuck using VS 2010 for a project, and noticed the following code still doesn't build using the non-standards compliant compiler: #include <stdio.h> #include <stdlib.h> int main (void) { char buffer[512]; snprintf(buffer, sizeof(buffer), "SomeString"); return 0; } (fails compilation with the error: C3861: 'snprintf': identifier not found) I remember this being the case way back with VS 2005 and am shocked to see it still hasn't been fixed. Does any one know if Microsoft has any plans to move their standard C libraries into the year 2010?

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  • Why calling ISet<dynamic>.Contains() compiles, but throws an exception at runtime?

    - by Andrey Breslav
    Please, help me to explain the following behavior: dynamic d = 1; ISet<dynamic> s = new HashSet<dynamic>(); s.Contains(d); The code compiles with no errors/warnings, but at the last line I get the following exception: Unhandled Exception: Microsoft.CSharp.RuntimeBinder.RuntimeBinderException: 'System.Collections.Generic.ISet<object>' does not contain a definition for 'Contains' at CallSite.Target(Closure , CallSite , ISet`1 , Object ) at System.Dynamic.UpdateDelegates.UpdateAndExecuteVoid2[T0,T1](CallSite site, T0 arg0, T1 arg1) at FormulaToSimulation.Program.Main(String[] args) in As far as I can tell, this is related to dynamic overload resolution, but the strange things are (1) If the type of s is HashSet<dynamic>, no exception occurs. (2) If I use a non-generic interface with a method accepting a dynamic argument, no exception occurs. Thus, it looks like this problem is related particularly with generic interfaces, but I could not find out what exactly causes the problem. Is it a bug in the compiler/typesystem, or legitimate behavior?

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  • SQL Server INSERT, Scope_Identity() and physical writing to disc

    - by TheBlueSky
    Hello everyone, I have a stored procedure that does, among other stuff, some inserts in different table inside a loop. See the example below for clearer understanding: INSERT INTO T1 VALUES ('something') SET @MyID = Scope_Identity() ... some stuff go here INSERT INTO T2 VALUES (@MyID, 'something else') ... The rest of the procedure These two tables (T1 and T2) have an IDENTITY(1, 1) column in each one of them, let's call them ID1 and ID2; however, after running the procedure in our production database (very busy database) and having more than 6250 records in each table, I have noticed one incident where ID1 does not match ID2! Although normally for each record inserted in T1, there is record inserted in T2 and the identity column in both is incremented consistently. The "wrong" records were something like that: ID1 Col1 ---- --------- 4709 data-4709 4710 data-4710 ID2 ID1 Col1 ---- ---- --------- 4709 4710 data-4709 4710 4709 data-4710 Note the "inverted", ID1 in the second table. Knowing not that much about SQL Server underneath operations, I have put the following "theory", maybe someone can correct me on this. What I think is that because the loop is faster than physically writing to the table, and/or maybe some other thing delayed the writing process, the records were buffered. When it comes the time to write them, they were wrote in no particular order. Is that even possible if no, how to explain the above mentioned scenario? If yes, then I have another question to rise. What if the first insert (from the code above) got delayed? Doesn't that mean I won't get the correct IDENTITY to insert into the second table? If the answer of this is also yes, what can I do to insure the insertion in the two tables will happen in sequence with the correct IDENTITY? I appreciate any comment and information that help me understand this. Thanks in advance.

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  • What should I do if a IOException is thrown?

    - by Roman
    I have the following 3 lines of the code: ServerSocket listeningSocket = new ServerSocket(earPort); Socket serverSideSocket = listeningSocket.accept(); BufferedReader in = new BufferedReader(new InputStreamReader(serverSideSocket.getInputStream())); The compiler complains about all of these 3 lines and its complain is the same for all 3 lines: unreported exception java.io.IOException; In more details, these exception are thrown by new ServerSocket, accept() and getInputStream(). I know I need to use try ... catch .... But for that I need to know what this exceptions mean in every particular case (how should I interpret them). When they happen? I mean, not in general, but in these 3 particular cases.

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  • Looking for marg_setValue fix in iPhoneOS

    - by John Smith
    I am trying to compile a library originally written for Cocoa. Things are good until it looks for the function marg_setValue(). It says there is a syntax error before char in marg_setValue(argumentList,argumentOffset,char,(char)lua_toboolean(state,luaArgument)); (it's talking about the third argument, not (char) ) I am trying to port LuaObjectiveCBridge to the iPhone. It has two choices, either using Runtime or Foundation. I have discovered there are some problems with foundation so I am trying runtime. But the compiler is not co-operating.

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  • Apache console accesses network drives, service does not?

    - by danspants
    I have an apache 2.2 server running Django. We have a network drive T: which we need constant access to within our Django app. When running Apache as a service, we cannot access this drive, as far as any django code is concerned the drive does not exist. If I add... <Directory "t:/"> Options Indexes FollowSymLinks MultiViews AllowOverride None Order allow,deny allow from all </Directory> to the httpd.conf file the service no longer runs, but I can start apache as a console and it works fine, Django can find the network drive and all is well. Why is there a difference between the console and the service? Should there be a difference? I have the service using my own log on so in theory it should have the same access as I do. I'm keen to keep it running as a service as it's far less obtrusive when I'm working on the server (unless there's a way to hide the console?). Any help would be most appreciated.

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  • NES Programming - Nametables?

    - by Jeffrey Kern
    Hello everyone, I'm wondering about how the NES displays its graphical muscle. I've researched stuff online and read through it, but I'm wondering about one last thing: Nametables. Basically, from what I've read, each 8x8 block in a NES nametable points to a location in the pattern table, which holds graphic memory. In addition, the nametable also has an attribute table which sets a certain color palette for each 16x16 block. They're linked up together like this: (assuming 16 8x8 blocks) Nametable, with A B C D = pointers to sprite data: ABBB CDCC DDDD DDDD Attribute table, with 1 2 3 = pointers to color palette data, with < referencing value to the left, ^ above, and ' to the left and above: 1<2< ^'^' 3<3< ^'^' So, in the example above, the blocks would be colored as so 1A 1B 2B 2B 1C 1D 2C 2C 3D 3D 3D 3D 3D 3D 3D 3D Now, if I have this on a fixed screen - it works great! Because the NES resolution is 256x240 pixels. Now, how do these tables get adjusted for scrolling? Because Nametable 0 can scroll into Nametable 1, and if you keep scrolling Nametable 0 will wrap around again. That I get. But what I don't get is how to scroll the attribute table wraps around as well. From what I've read online, the 16x16 blocks it assigns attributes for will cause color distortions on the edge tiles of the screen (as seen when you scroll left to right and vice-versa in SMB3). The concern I have is that I understand how to scroll the nametables, but how do you scroll the attribute table? For intsance, if I have a green block on the left side of the screen, moving the screen to right should in theory cause the tiles to the right to be green as well until they move more into frame, to which they'll revert to their normal colors.

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  • Request-local storage in ASP.NET (accessible to the code from IHttpModule implementation)

    - by IgorK
    I need to have some object hanging around between two events I'm interested in: PreRequestHandlerExecute (where I create an instance of my object and want to save it) and PostRequestHandlerExecute (where I want to get to the object). After the second event the object is not needed for my purposes and should be discarded either by storage or my explicit action. So the ideal context where my object should be stored is per request (with guaranteed no sharing issues when different threads are serving requests... or processes/servers :) ) Take into account that actual implementation I can do is being made from a HttpModule and is supposed to be a pluggable solution for already written web apps (so the option to provide some state using static/instance variables in Global.asax doesn't look good - I will have to modify Global.asax on every web application). Cache seems to be too broad for this use. I tried to see whether httpContext.Application (of type HttpApplicationState) is good for me or not, but cannot get whether it is exactly per HttpApplication instance or not (AFAIK you can have several instances of HttpApplications used on different threads and therefore serving several requests simultaneously - then using storage shared between threads will not work correctly; otherwise I would use it because one HttpApplication instance serves exactly one request at a time). Something could be done with storing state on the HttpModule instances if I know for sure that it's exactly bound 1-to-1 with every HttpApplication instance running (but again I need a proof that HttpApplication instance is 1-to-1 with my HttpModule's instance). Any valuable and reputable links on these topics are much appreciated... Would be great to find something particularly well-suited for per request situation (because otherwise I may end up with something ulgy... probably either some 'broader' scoped storage and some hacks to have different keys in the storage for different requests, OR using a thread-local thing and in this way commit to the theory that IIS/ASP.NET will not ever serve first event from one thread and the second event from the other thread and so on)

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  • Modifying reference member from const member function in C++

    - by Philipp
    I am working on const-correctness of my code and just wondered why this code compiles: class X { int x; int& y; public: X(int& _y):y(_y) { } void f(int& newY) const { //x = 3; would not work, that's fine y = newY; //does compile. Why? } }; int main(int argc, char **argv) { int i1=0, i2=0; X myX(i1); myX.f(i2); ... } As far as I understand, f() is changing the object myX, although it says to be const. How can I ensure my compiler complains when I do assign to y? (Visual C++ 2008) Thank a lot!

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  • Modelling in Agile Development

    - by bertzzie
    I'm writing a bachelor dissertation report where I'm developing a system with Agile methodology. Given that the development is an one man show, of course the "Agile" I did was not really agile at all (from my understanding at least). So I want some perspective from SO crowds, who is of course a professional, real world, developer with tons of experience. I think real world experience is better than the theory and experiments that I did. My question is: Do we model during development time when using Agile? UML? DFD? Or a Functional Specification is enough1? If modelling is not really necessary, what do we use to communicate to the user, as the user almost always won't understand UML or DFD? For my system, I use UI & UX Design with heavy prototyping, but then I don't have time to draw UML any more. Which one is better? 1 http://www.joelonsoftware.com/articles/fog0000000036.html I hope the question's not "subjective and argumentative" as I know this question exist because of my lack of understanding in the agile development. If it is, could someone just give me a pointer or reference about that? Possible duplicate: Do you use UML in Agile development practices?

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  • Standard (cross-platform) way for bit manipulation

    - by Kiril Kirov
    As are are different binary representation of the numbers (for example, take big/little endian), is this cross-platform: some_unsigned_type variable = some_number; // set n-th bit, starting from 1, // right-to-left (least significant-to most significant) variable |= ( 1 << ( n - 1 ) ); // clear the same bit: variable &= ~( 1 << ( n - 1 ) ); In other words, does the compiler always take care of the different binary representation of the unsigned numbers, or it's platform-specific? And what if variable is signed integral type (for example, int) and its value is zero positive negative? What does the Standard say about this? P.S. And, yes, I'm interesting in both - C and C++, please don't tell me they are different languages, because I know this :) I can paste real example, if needed, but the post will become too long

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  • error handling strategies in C?

    - by Leo
    Given the code below: typedef struct {int a;} test_t; arbitrary_t test_dosomething(test_t* test) { if (test == NULL) { //options: //1. print an error and let it crash //e.g. fprintf(stderr, "null ref at %s:%u", __FILE__, __LINE__); //2. stop the world //e.g. exit(1); //3. return (i.e. function does nothing) //4. attempt to re-init test } printf("%d", test->a); //do something w/ test } I want to get a compiler error if test is ever NULL, but I guess that's not possible in C. Since I need to do null checking at runtime, what option is the most proper way to handle it?

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  • C# extern int ? How do I make a global var across classes and namespaces ?

    - by dr d b karron
    Dear C#'ers; As an old C/C++ programmer, I want to keep a global int counter across all of MY namespaces and classes. Public static extern int EventCount; Is not working; the VS2010 compiler won't let me have an extern int. Even with a DLLImport. [DllImport ( "SilverlightApplication37.dll" )] public static extern int EventCount; VS2010 complains Error 1 The modifier 'extern' is not valid for this item so how do i have a global int across all my code ? Cheers! dr.K

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  • What TypeScript pattern can I use to enforce that a function gets a property?

    - by Matt York
    In JavaScript I can do this: function f() {} f.prop = "property"; I want this in TypeScript, but with type checking. What TypeScript pattern can I use to enforce that a function gets a property? Could I use an interface? interface functionWithProperty { (): any; prop: string; } This seems to be a valid interface in TypeScript, but how do I implement this interface such that the TypeScript compiler checks that prop is set? I saw this example: var f : functionWithProperty = (() => { var _f : any = function () { }; _f.prop = "blah"; return _f; }()); But this doesn't work because I can remove _f.prop = "blah"; and everything will still compile. I need to enforce that prop is set.

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  • saving a records containing a member of type string to a file (Delphi, Windows)

    - by wonderer
    I have a record that looks similar to: type TNote = record Title : string; Note : string; Index : integer; end; Simple. The reason I chose to set the variables as string (as opposed to an array of chars) is that I have no idea how long those strings are going to be. They can be 1 char long, 200 or 2000. Of course when I try to save the record to a type file (file of...) the compiler complains that I have to give a size to string. Is there a way to overcome this? or a way to save those records to an untyped file and still maintain a sort of searchable way? Please do not point me to possible solutions, if you know the solution please post code. Thank you

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  • Using type hints in Clojure for Java return values

    - by mikera
    I'm working on some Java / Clojure interoperability and came across a reflection warning for the following code: (defn load-image [resource-name] (javax.imageio.ImageIO/read (.getResource (class javax.imageio.ImageIO) resource-name))) => Reflection warning, clojure/repl.clj:37 - reference to field read can't be resolved. I'm surprised at this because getResource always returns a URL and I would therefore expect the compiler to use the appropriate static method in javax.imageio.ImageIO/read. The code works fine BTW so it is clearly finding the right method at run time. So two questions: Why is this returning a reflection warning? What type hint do I need to fix this?

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  • What about race condition in multithreaded reading?

    - by themoob
    Hi, According to an article on IBM.com, "a race condition is a situation in which two or more threads or processes are reading or writing some shared data, and the final result depends on the timing of how the threads are scheduled. Race conditions can lead to unpredictable results and subtle program bugs." . Although the article concerns Java, I have in general been taught the same definition. As far as I know, simple operation of reading from RAM is composed of setting the states of specific input lines (address, read etc.) and reading the states of output lines. This is an operation that obviously cannot be executed simultaneously by two devices and has to be serialized. Now let's suppose we have a situation when a couple of threads access an object in memory. In theory, this access should be serialized in order to prevent race conditions. But e.g. the readers/writers algorithm assumes that an arbitrary number of readers can use the shared memory at the same time. So, the question is: does one have to implement an exclusive lock for read when using multithreading (in WinAPI e.g.)? If not, why? Where is this control implemented - OS, hardware? Best regards, Kuba

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