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  • C question: error: expected ')' before '*' token

    - by lhw
    ===EDIT I apologize for not putting the pcb struct into the code snippet. There is a struct called pcb defined in above the two structs I originally posted. Namely, typedef struct{ UINT32 proc; struct pcb *link; }pcb; Hi, I asked a question regarding structs in C a few minutes ago and got an answer blazing fast. But now I'm facing another problem, namely the error in the title of this question. I'm trying to implement a simple priority queue in C using arrays of queues. However, when I try to declare a function on pcb_pQ structure, I get the above error. I have the structs clearly defined in the heard file. In the header file: typedef struct{ pcb *head; pcb *tail; SINT32 size; } pcb_Q; typedef struct pcb_pQ { pcb_Q queues[5]; SINT32 size; } pcb_pQ; Function prototype in header file: /*priority queue operations*/ VOID pcb_pq_enqueue(pcb_pQ*, pcb*); Function impelmentation in .c file: VOID pcb_pq_enqueue(pcb_pQ* pcb_pQ, pcb* pcb) { pcb_Q* pcb_Q_p; int priority; priority = pcb->proc_priority; pcb_Q_p = &pcb_pQ->queues[priority]; pcb_enqueue(pcb_Q_p, pcb); } When I try to compile the above code, I get an "error: expected ')' before '*' token". This error is pointing to the function signature in the .c file, namely VOID pcb_pq_enqueue(pcb_pQ* pcb_pQ, pcb* pcb) { But I am not sure why I am getting this error, could someone give me a hand? Thanks a lot.

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  • Clone existing structs with different alignment in Visual C++

    - by Crend King
    Is there a way to clone an existing struct with different member alignment in Visual C++? Here is the background: I use an 3rd-party library, which uses several structs. To fill up the structs, I pass the address of the struct instances to some functions. Unfortunately, the functions only returns unaligned buffer, so that data of some members are always wrong. /Zp is out of choice, since it breaks the other parts of the program. I know #pragma pack modifies the alignment of the following struct, but I would like to avoid copying the structs into my code, for the definitions in the library might change in the future. Sample code: test.h: struct am_aligned { BYTE data1[10]; ULONG data2; }; test.cpp: #include "test.h" // typedef alignment(1) struct am_aligned am_unaligned; int APIENTRY wWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpCmdLine, int nCmdShow) { char buffer[20] = {}; for (int i = 0; i < sizeof(unaligned_struct); i++) { buffer[i] = i; } am_aligned instance = *(am_aligned*) buffer; return 0; } Consider am_aligned is defined in the library header file. am_unaligned is my custom declaration, and only effective in test.cpp. The commented line does not work of course. instance.data2 is 0x0f0e0d0c, while 0x0d0c0b0a is desired. Thanks for help!

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  • Coordinating typedefs and structs in std::multiset (C++)

    - by Sarah
    I'm not a professional programmer, so please don't hesitate to state the obvious. My goal is to use a std::multiset container (typedef EventMultiSet) called currentEvents to organize a list of structs, of type Event, and to have members of class Host occasionally add new Event structs to currentEvents. The structs are supposed to be sorted by one of their members, time. I am not sure how much of what I am trying to do is legal; the g++ compiler reports (in "Host.h") "error: 'EventMultiSet' has not been declared." Here's what I'm doing: // Event.h struct Event { public: bool operator < ( const Event & rhs ) const { return ( time < rhs.time ); } double time; int eventID; int hostID; }; // Host.h ... void calcLifeHist( double, EventMultiSet * ); // produces compiler error ... void addEvent( double, int, int, EventMultiSet * ); // produces compiler error // Host.cpp #include "Event.h" ... // main.cpp #include "Event.h" ... typedef std::multiset< Event, std::less< Event > > EventMultiSet; EventMultiSet currentEvents; EventMultiSet * cePtr = &currentEvents; ... Major questions Where should I include the EventMultiSet typedef? Are my EventMultiSet pointers obviously problematic? Is the compare function within my Event struct (in theory) okay? Thank you very much in advance.

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  • Syntax for finding structs in multisets - C++

    - by Sarah
    I can't seem to figure out the syntax for finding structs in containers. I have a multiset of Event structs. I'm trying to find one of these structs by searching on its key. I get the compiler error commented below. struct Event { public: bool operator < ( const Event & rhs ) const { return ( time < rhs.time ); } bool operator > ( const Event & rhs ) const { return ( time > rhs.time ); } bool operator == ( const Event & rhs ) const { return ( time == rhs.time ); } double time; int eventID; int hostID; int s; }; typedef std::multiset< Event, std::less< Event > > EventPQ; EventPQ currentEvents; double oldRecTime = 20.0; EventPQ::iterator ceItr = currentEvents.find( EventPQ::key_type( oldRecTime ) ); // no matching function call I've tried a few permutations to no avail. I thought defining the conditional equality operator was going to be enough.

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  • Overriding Equals method in Structs

    - by devoured elysium
    I've looked for overriding guidelines for structs, but all I can find is for classes. At first I thought I wouldn't have to check to see if the passed object was null, as structs are value types and can't be null. But now that I come to think of it, as equals signature is public bool Equals(object obj) it seems there is nothing preventing the user of my struct to be trying to compare it with an arbitrary reference type. My second point concerns the casting I (think I) have to make before I compare my private fields in my struct. How am I supposed to cast the object to my struct's type? C#'s as keyword seems only suitable for reference types. Thanks

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  • Marshalling non-Blittable Structs from C# to C++

    - by Greggo
    I'm in the process of rewriting an overengineered and unmaintainable chunk of my company's library code that interfaces between C# and C++. I've started looking into P/Invoke, but it seems like there's not much in the way of accessible help. We're passing a struct that contains various parameters and settings down to unmanaged codes, so we're defining identical structs. We don't need to change any of those parameters on the C++ side, but we do need to access them after the P/Invoked function has returned. My questions are: What is the best way to pass strings? Some are short (device id's which can be set by us), and some are file paths (which may contain Asian characters) Should I pass an IntPtr to the C# struct or should I just let the Marshaller take care of it by putting the struct type in the function signature? Should I be worried about any non-pointer datatypes like bools or enums (in other, related structs)? We have the treat warnings as errors flag set in C++ so we can't use the Microsoft extension for enums to force a datatype. Is P/Invoke actually the way to go? There was some Microsoft documentation about Implicit P/Invoke that said it was more type-safe and performant. For reference, here is one of the pairs of structs I've written so far: C++ /** Struct used for marshalling Scan parameters from managed to unmanaged code. */ struct ScanParameters { LPSTR deviceID; LPSTR spdClock; LPSTR spdStartTrigger; double spinRpm; double startRadius; double endRadius; double trackSpacing; UINT64 numTracks; UINT32 nominalSampleCount; double gainLimit; double sampleRate; double scanHeight; LPWSTR qmoPath; //includes filename LPWSTR qzpPath; //includes filename }; C# /// <summary> /// Struct used for marshalling scan parameters between managed and unmanaged code. /// </summary> [StructLayout(LayoutKind.Sequential)] public struct ScanParameters { [MarshalAs(UnmanagedType.LPStr)] public string deviceID; [MarshalAs(UnmanagedType.LPStr)] public string spdClock; [MarshalAs(UnmanagedType.LPStr)] public string spdStartTrigger; public Double spinRpm; public Double startRadius; public Double endRadius; public Double trackSpacing; public UInt64 numTracks; public UInt32 nominalSampleCount; public Double gainLimit; public Double sampleRate; public Double scanHeight; [MarshalAs(UnmanagedType.LPWStr)] public string qmoPath; [MarshalAs(UnmanagedType.LPWStr)] public string qzpPath; }

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  • a nicer way to create structs in a loop

    - by sandra
    Hi guys, I haven't coded in C++ in ages. And recently, I'm trying to work on something involving structs. Like this typedef struct{ int x; int y; } Point; Then in a loop, I'm trying to create new structs and put pointers to them them in a list. Point* p; int i, j; while (condition){ // compute values for i and j with some function... p = new Point; p* = {i, j}; //initialize my struct. list.append(p); //append this pointer to my list. } Now, my question is it possible to simplify this? I mean, the pointer variable *p outside of the loop and calling p = new Point inside the loop. Isn't there a better/nicer syntax for this?

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  • C dynamic memory allocation for table of structs

    - by JosiP
    Hi here is my code. I want to dynamincly change no of elemnts in table with structs __state: typedef struct __state{ long int timestamp; int val; int prev_value; }*state_p, state_t; int main(int argc, char **argv){ int zm; int previous_state = 0; int state = 0; int i = 0; int j; state_p st; //here i want to have 20 structs st. st = (state_p) malloc(sizeof(state_t) * 20); while(1){ previous_state = state; scanf("%d", &state); printf("%d, %d\n", state, previous_state); if (previous_state != state){ printf("state changed %d %d\n", previous_state, state); // here i got compile error: main.c: In function ‘main’: main.c:30: error: incompatible type for argument 1 of ‘save_state’ main.c:34: error: invalid type argument of ‘->’ main.c:34: error: invalid type argument of ‘->’ save_state(st[i],previous_state, state); } i++; } return 0; } I suppose i have to change that st[i] to smth like st+ptr ? where pointer is incermeting in each loop iteration ? Or am I wrong ? When i change code: initialization into state_p st[20] and in each loop iteration i put st[i] = (state_p)malloc(sizeof(state_t)) everything works fine, but i want to dynammicly change number of elemets in that table. Thx in advance for any help

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  • How to extract ALL typedefs and structs and unions from c++ source

    - by Michael Wells
    I have inherited a Visual Studio project that contains hundreds of files. I would like to extract all the typedefs, structs and unions from each .h/.cpp file and put the results in a file). Each typdef/struct/union should be on one line in the results file. This would make sorting much easier. typdef int myType; struct myFirstStruct { char a; int b;...}; union Part_Number_Serial_Number_Part_2_Response_Message_Type {struct{Message_Response_Head_Type Head; Part_Num_Serial_Num_Part_2_Report_Array Part_2_Report; Message_Tail_Type Tail;} Data; BYTE byData[140];}myUnion; struct { bool c; int d;...}mySecondStruct; My problem is, I do not know what to look for (grammar of typedef/structs/unions) using a regular expression. I cannot believe that nobody has done this before (I googled and have not found anything on this). Does anyone know the regular expressions for these? (Note some are commented out using // others /* */) Or a tool to accomplish this. Edit: I am toying with the idea of autogenerating source code and/or dialogs for modifying messages that use the underlying typedef/struct/union. I was going to use the output to generate an XML file that could be used for this reason. The source for these are in C/C++ and used in almost all my projects. These projects are usually NOT in C/C++. By using the XML version I would only need to update/add the typedef/struct/union only in one place and all the projects would be able to autogen the source and/or dialogs.

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  • Convert array of hashes to array of structs?

    - by keruilin
    Let's say I have two objects: User and Race. User has two attributes: first_name, last_name. And Race has three attributes: course, start_time, end_time. Now let's say I create an array of hashes like this: user_races = races.map{ |race| {:user = race.user, :race = race} } How do I then convert user_races into an array of structs, keeping in mind that I want to be able to access the attributes of both user and race from the struct element?

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  • Assigning values to chars in structs - c

    - by mrblippy
    Hi, i have been having trouble getting my head around allowing a user to enter words into structs. the struct i am using is below struct class { char class_num[4]; char *class_name } if anyone could point me how to do this or at least point me in the right direction that wuld be great. thanks

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  • ColdFusion structs Direct Assignment vs object literal notation.

    - by Tom Hubbard
    The newer versions of ColdFusion (I believe CF 8 and 9) allow you to create structs with object literal notation similar to JSON. My question is, are there specific benefits (execution efficiency maybe) to using object literal notation over individual assignments for data that is essentially static? For example: With individual assignments you would do something like this: var user = {}; user.Fname = "MyFirstnam"; user.Lname = "MyLastName"; user.titles = []; ArrayAppend(user.titles,'Mr'); ArrayAppend(user.titles,'Dr.'); Whereas with object literals you would do something like. var user = {Fname = "MyFirstnam", Lname = "MyLastName", titles = ['Mr','Dr']}; Now this limited example is admittedly simple, but if titles was an array of structures (Say an array of addresses), the literal notation becomes awkward to work with.

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  • Using C Structs which contains ObjC Objects?

    - by GuidoMB
    I'm using C structs in objc and I've created a function that assembles the structure like the one from the Cocoa API. The things is that this structure is not like NSRect o NSPoint this structure packs objc objects soo I'm seeing a potential memory leak here. Do I need to provide a function to 'release' the structure? I'am not creating a ISKNewsCategory class because there will be no behavior but Do you think this is a good approach or I should define the class even doe there will be no behavior? typedef struct ISK_NewsCategory { NSString *name; NSString *code } ISKNewsCategory; NS_INLINE ISKNewsCategory ISKMakeNewsCategory(NSString *name, NSString *code) { ISKNewsCategory category; category.name = [name retain]; category.code = [code retain]; return category; }

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  • In Clojure - How do I access keys in a vector of structs

    - by Nick
    I have the following vector of structs: (defstruct #^{:doc "Basic structure for book information."} book :title :authors :price) (def #^{:doc "The top ten Amazon best sellers on 16 Mar 2010."} best-sellers [(struct book "The Big Short" ["Michael Lewis"] 15.09) (struct book "The Help" ["Kathryn Stockett"] 9.50) (struct book "Change Your Prain, Change Your Body" ["Daniel G. Amen M.D."] 14.29) (struct book "Food Rules" ["Michael Pollan"] 5.00) (struct book "Courage and Consequence" ["Karl Rove"] 16.50) (struct book "A Patriot's History of the United States" ["Larry Schweikart","Michael Allen"] 12.00) (struct book "The 48 Laws of Power" ["Robert Greene"] 11.00) (struct book "The Five Thousand Year Leap" ["W. Cleon Skousen","James Michael Pratt","Carlos L Packard","Evan Frederickson"] 10.97) (struct book "Chelsea Chelsea Bang Bang" ["Chelsea Handler"] 14.03) (struct book "The Kind Diet" ["Alicia Silverstone","Neal D. Barnard M.D."] 16.00)]) I would like to sum the prices of all the books in the vector. What I have is the following: (defn get-price "Same as print-book but handling multiple authors on a single book" [ {:keys [title authors price]} ] price) Then I: (reduce + (map get-price best-sellers)) Is there a way of doing this without mapping the "get-price" function over the vector? Or is there an idiomatic way of approaching this problem?

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  • Returning an array of tm* structs from a function

    - by paultop6
    Hi Guys, Im trying to create an array of tm* structs, and then return them at the end of the function. This is what i have at the moment: struct tm* BusinessLogicLayer::GetNoResponceTime() { struct tm* time_v[3]; struct tm* time_save; int s = 3; time_save = LastSavedTime(); time_v[0] = time_save; sleep(5); time_save = LastSavedTime(); time_v[1] = time_save; sleep(5); time_save = LastSavedTime(); time_v[2] = time_save; return time_v; } I understand that given the code i have now it will not be possible to return the array, because it will be destroyed when the function ends. Can anyone help me with regards to how i would go about being able to access the array from the returned value after the function has ended? Regards Paul

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  • algorithm to find overlaps

    - by Gary
    Hey, Basically I've got some structs of type Ship which are going to go on a board which can have a variable width and height. The information about the ships is read in from a file, and I just need to know the best way to make sure that none of the ships overlap. Here is the structure of Ship: int x // x position of first part of ship int y // y position of first part of ship char dir // direction of the ship, either 'N','S','E' or 'W' int length // length of the ship Also, what would be a good way to handle the directions. Something cleaner than using a switch statement and using a different condition for each direction. Any help would be greatly appreciated!

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  • C++ a class with an array of structs, without knowing how large an array I need

    - by Dominic Bou-Samra
    New to C++, and for that matter OO programming. I have a class with fields like firstname, age, school etc. I need to be able to store other information like for instance, where they have travelled, and what year it was in. I cannot declare another class specifically to hold travelDestination and what year, so I think a struct might be best. This is just an example: struct travel { string travelDest; string year; }; The issue is people are likely to have travelled different amounts. I was thinking of just having an array of travel structs to hold the data. But how do I create a fixed sized array to hold them, without knowing how big I need it to be? Perhaps I am going about this the completely wrong way, so any suggestions as to a better way would be appreciated.

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  • Initializing structs in C++

    - by Neil Butterworth
    As an addendum to this question, what is going on here: #include <string> using namespace std; struct A { string s; }; int main() { A a = {0}; } Obviously, you can't set a std::string to zero. Can someone provide an explanation (backed with references to the C++ Standard, please) about what is actually supposed to happen here? And then explain for example): int main() { A a = {42}; } Are either of these well-defined? Once again an embarrassing question for me - I always give my structs constructors, so the issue has never arisen before.

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  • How to name variables wich are structs

    - by evilpie
    Hello, i often work on private projects using the WinApi, and as you might know, it has thousands of named and typedefed structs like MEMORY_BASIC_INFORMATION. I will stick to this one in my question, what still is preferred, or better when you want to name a variable of this type. Is there some kind of style guide for this case? For example if i need that variable for the VirtualQueryEx function. Some ideas: MEMORY_BASIC_INFORMATION memoryBasicInformation; MEMORY_BASIC_INFORMATION memory_basic_information; Just use the name of the struct non captialized and with or without the underlines. MEMORY_BASIC_INFORMATION basicInformation; MEMORY_BASIC_INFORMATION information; Short form? MEMORY_BASIC_INFORMATION mbi; I often see this style, using the abbreviation of the struct name. MEMORY_BASIC_INFORMATION buffer; VirtualQueryEx defines the third parameter lpBuffer (where you pass the pointer to the struct), so using this name might be an idea, too. Cheers

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  • Sorting array of structs

    - by mrblippy
    Hi, i am having trouble making a method to sort an array of structs. i am tring to sort them in ascending order based on classcode. any help you could give would be appreciated struct unit { char classcode[4]; char *classname; }; void insertion_sort(struct unit u[], int n) { int j, p; struct unit tmp[1]; for(p = 1; p < n; p++) { tmp[0] = u[p]; for(j = p; j > 0 && (strcmp(tmp[j-1].classcode, tmp[p].classcode) > 0); j--) u[j] = u[j-1]; u[j] = tmp[0]; } }

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  • Initialising structs in C++

    - by Neil Butterworth
    As an addendum to this question, what is going on here: #include <string> using namespace std; struct A { string s; }; int main() { A a = {0}; } Obviously, you can't set a std::string to zero. Can someone provide an explanation (backed with references to the C++ Standard, please) about what is actually supposed to happen here? And then explain for example): int main() { A a = {42}; } Are either of these well-defined? Once again an embarrassing question for me - I always give my structs constructors, so the issue has never arisen before.

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  • How to name variables which are structs

    - by evilpie
    Hello, i often work on private projects using the WinApi, and as you might know, it has thousands of named and typedefed structs like MEMORY_BASIC_INFORMATION. I will stick to this one in my question, what still is preferred, or better when you want to name a variable of this type. Is there some kind of style guide for this case? For example if i need that variable for the VirtualQueryEx function. Some ideas: MEMORY_BASIC_INFORMATION memoryBasicInformation; MEMORY_BASIC_INFORMATION memory_basic_information; Just use the name of the struct non capitalized and with or without the underlines. MEMORY_BASIC_INFORMATION basicInformation; MEMORY_BASIC_INFORMATION information; Short form? MEMORY_BASIC_INFORMATION mbi; I often see this style, using the abbreviation of the struct name. MEMORY_BASIC_INFORMATION buffer; VirtualQueryEx defines the third parameter lpBuffer (where you pass the pointer to the struct), so using this name might be an idea, too. Cheers

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