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  • read text file in xcode

    - by danielDhobbs
    hello. i tried to read text file in xcode but this "EXC_BAD_ACCESS message showed up when i tried to build my program here is my code and i put inputA.txt file in the same folder with project file my friend told me that i should put txt file in debug folder is this why i cannot read txt file in this code? please help me... macbook user. int main (int argc, const char * argv[]) { FILE* fp; char mychar; char arr[50][2] = {0, }; int i = 0; int j, k; graphType* G_; G_ = (graphType*)malloc(sizeof(graphType)); Create(G_); fp = fopen("inputA.txt", "r"); //fp = fopen("inputB.txt", "r"); //fp = fopen("inputC.txt", "r"); while(1){ for(j = 0 ; j < 2 ; j++){ mychar = fgetc(fp); if(mychar == EOF) break; else if(mychar == ' ') continue; arr[i][j] = mychar; } i++; }

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  • Is there a tool that can refactor this C code correctly?

    - by Alex
    Lets say I have the following code (the array* function are what we use for resizable arrays and they operate on pointers-to-arrays that are null initialized): typedef struct MyStruct { int i; } MyStruct; MyStruct* GetNewMyStruct(int i) { MyStruct* s = malloc(sizeof(MyStruct)); s->i = i; return s; } int SomeFunction(int number, MyStruct *elem) { MyStruct **structs = NULL; int i; for (i = 0; i < number; i++) arrayPush(&structs, GetNewMyStruct(i)); arrayPush(&structs, elem); return arraySize(&structs); } I decide that SomeFunction is too large and I want refactor it. Currently where I work we use VisualAssist X, which has some refactoring capabilities, but when I use it on this it does not work correctly. If I attempt to use it to refactor out the loop, this is what I get: void MyMethod( int number, MyStruct ** structs ) { int i; for (i = 0; i < number; i++) arrayPush(&structs, GetNewMyStruct(i)); } int SomeFunction(int number, MyStruct *elem) { MyStruct **structs = NULL; MyMethod(number, structs); arrrayPush(&structs, elem); return arraySize(&structs); } This is not correct. MyMethod should take a MyStruct ***, not a MyStruct **. This is because the code I'm refactoring takes the address of structs. The result is that the refactored version will always return 1 (since only one object has been pushed into my array) rather than number+1. Are there other tools out there that do this type of refactoring correctly?

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  • I can't figure out why this fps counter is inaccurate.

    - by rmetzger
    I'm trying to track frames per second in my game. I don't want the fps to show as an average. I want to see how the frame rate is affected when I push keys and add models etc. So I am using a variable to store the current time and previous time, and when they differ by 1 second, then I update the fps. My problem is that it is showing around 33fps but when I move the mouse around really fast, the fps jumps up to 49fps. Other times, if I change a simple line of code elsewhere not related to the frame counter, or close the project and open it later, the fps will be around 60. Vsync is on so I can't tell if the mouse is still effecting the fps. Here is my code which is in an update function that happens every frame: FrameCount++; currentTime = timeGetTime (); static unsigned long prevTime = currentTime; TimeDelta = (currentTime - prevTime) / 1000; if (TimeDelta > 1.0f) { fps = FrameCount / TimeDelta; prevTime = currentTime; FrameCount = 0; TimeDelta = 0; } Here are the variable declarations: int FrameCount; double fps, currentTime, prevTime, TimeDelta, TimeElapsed; Please let me know what is wrong here and how to fix it, or if you have a better way to count fps. Thanks!!!!!! I am using DirectX 9 btw but I doubt that is relevant, and I am using PeekMessage. Should I be using an if else statement instead? Here is my message processing loop: MSG msg; ZeroMemory (&msg, sizeof (MSG)); while (msg.message != WM_QUIT) { if (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE)) { TranslateMessage (&msg); DispatchMessage (&msg); } Update (); RenderFrame (); }

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  • Optimizing a shared buffer in a producer/consumer multithreaded environment

    - by Etan
    I have some project where I have a single producer thread which writes events into a buffer, and an additional single consumer thread which takes events from the buffer. My goal is to optimize this thing for a single machine to achieve maximum throughput. Currently, I am using some simple lock-free ring buffer (lock-free is possible since I have only one consumer and one producer thread and therefore the pointers are only updated by a single thread). #define BUF_SIZE 32768 struct buf_t { volatile int writepos; volatile void * buffer[BUF_SIZE]; volatile int readpos;) }; void produce (buf_t *b, void * e) { int next = (b->writepos+1) % BUF_SIZE; while (b->readpos == next); // queue is full. wait b->buffer[b->writepos] = e; b->writepos = next; } void * consume (buf_t *b) { while (b->readpos == b->writepos); // nothing to consume. wait int next = (b->readpos+1) % BUF_SIZE; void * res = b->buffer[b->readpos]; b->readpos = next; return res; } buf_t *alloc () { buf_t *b = (buf_t *)malloc(sizeof(buf_t)); b->writepos = 0; b->readpos = 0; return b; } However, this implementation is not yet fast enough and should be optimized further. I've tried with different BUF_SIZE values and got some speed-up. Additionaly, I've moved writepos before the buffer and readpos after the buffer to ensure that both variables are on different cache lines which resulted also in some speed. What I need is a speedup of about 400 %. Do you have any ideas how I could achieve this using things like padding etc?

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  • recommended format to save time with MJD + BCD format in database

    - by pierr
    Hi, There is a time represented in MJD and BCD format with 5 bytes .I am wondering what is the recommended format to save this date-time in the sqlite database so that user can search against it ? My first attempt is to save it just as it is, that is a 5 bytes string. The user will use the same format to search and the result will be converted to unix time by the user with following code. However, later, I was suggested to save the time in the integer - the UTC time, for example. But I can not find a standard way to do the conversion. I feel this is a common issue and would like to hear your comments. time_t sidate_to_unixtime(unsigned char sidate[]) { int k = 0; struct tm tm; double mjd; /* check for the undefined value */ if ((sidate[0] == 0xff) && (sidate[1] == 0xff) && (sidate[2] == 0xff) && (sidate[3] == 0xff) && (sidate[4] == 0xff)) { return -1; } memset(&tm, 0, sizeof(tm)); mjd = (sidate[0] << 8) | sidate[1]; tm.tm_year = (int) ((mjd - 15078.2) / 365.25); tm.tm_mon = (int) (((mjd - 14956.1) - (int) (tm.tm_year * 365.25)) / 30.6001); tm.tm_mday = (int) mjd - 14956 - (int) (tm.tm_year * 365.25) - (int) (tm.tm_mon * 30.6001); if ((tm.tm_mon == 14) || (tm.tm_mon == 15)) k = 1; tm.tm_year += k; tm.tm_mon = tm.tm_mon - 2 - k * 12; tm.tm_sec = bcd_to_integer(sidate[4]); tm.tm_min = bcd_to_integer(sidate[3]); tm.tm_hour = bcd_to_integer(sidate[2]); return mktime(&tm); }

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  • Image insert problem php sqlserver

    - by Termedi
    Hi I can not save image inside a sql server 2000 database. datatype is image here is the code: // Image Upload <?php include('config.php'); if(is_uploaded_file($_FILES['userfile']['tmp_name'])) { $fileName = $_FILES['userfile']['name']; $tmpName = $_FILES['userfile']['tmp_name']; $fileSize = $_FILES['userfile']['size']; $fileType = $_FILES['userfile']['type']; $size = filesize($tmpName); set_magic_quotes_runtime(0);//to desactive the default escape spacials caracters made by PHP in the externes files $img_binaire = base64_encode(fread(fopen(str_replace("'","''",$tmpName), "r"), $size)); $query = "INSERT INTO test_image (image_name, image_content, image_size) ". "VALUES ('{$fileName}','{$img_binaire}', '{$size}')"; odbc_exec($conn, $query) or die('Error, query failed'); echo "<br>File $fileName uploaded<br>"; echo "<br>File Size: $fileSize <br>"; } ?> // Image Show <?php include('config.php'); $sql = "select * from test_image where id =2"; $rsl = odbc_exec($conn, $sql); $image_info = odbc_fetch_array($rsl); //$count = sizeof($image_info['image_content']); //header('Accept-Ranges: bytes'); //header('Content-Length: '.$image_info['image_size']); //header("Content-length: 17397"); header('Content-Type: image/jpeg'); echo base64_decode($image_info['image_content']); //echo bindec($image_info['image_content']); ?> Error: Warning: odbc_exec() [function.odbc-exec]: SQL error: [Microsoft][ODBC SQL Server Driver][SQL Server]Operand type clash: text is incompatible with image, SQL state 22005 in SQLExecDirect in C:\xampp\htdocs\test\upload.php on line 25 Error, query failed

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  • How to asynchronously read to std::string using Boost::asio?

    - by SpyBot
    Hello. I'm learning Boost::asio and all that async stuff. How can I asynchronously read to variable user_ of type std::string? Boost::asio::buffer(user_) works only with async_write(), but not with async_read(). It works with vector, so what is the reason for it not to work with string? Is there another way to do that besides declaring char user_[max_len] and using Boost::asio::buffer(user_, max_len)? Also, what's the point of inheriting from boost::enable_shared_from_this<Connection> and using shared_from_this() instead of this in async_read() and async_write()? I've seen that a lot in the examples. Here is a part of my code: class Connection { public: Connection(tcp::acceptor &acceptor) : acceptor_(acceptor), socket_(acceptor.get_io_service(), tcp::v4()) { } void start() { acceptor_.get_io_service().post( boost::bind(&Connection::start_accept, this)); } private: void start_accept() { acceptor_.async_accept(socket_, boost::bind(&Connection::handle_accept, this, placeholders::error)); } void handle_accept(const boost::system::error_code& err) { if (err) { disconnect(); } else { async_read(socket_, boost::asio::buffer(user_), boost::bind(&Connection::handle_user_read, this, placeholders::error, placeholders::bytes_transferred)); } } void handle_user_read(const boost::system::error_code& err, std::size_t bytes_transferred) { if ( err or (bytes_transferred != sizeof(user_)) ) { disconnect(); } else { ... } } ... void disconnect() { socket_.shutdown(tcp::socket::shutdown_both); socket_.close(); socket_.open(tcp::v4()); start_accept(); } tcp::acceptor &acceptor_; tcp::socket socket_; std::string user_; std::string pass_; ... };

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  • How can I free all allocated memory at once?

    - by Tommy
    Here is what I am working with: char* qdat[][NUMTBLCOLS]; char** tdat[]; char* ptr_web_data; // Loop thru each table row of the query result set for(row_index = 0; row_index < number_rows; row_index++) { // Loop thru each column of the query result set and extract the data for(col_index = 0; col_index < number_cols; col_index++) { ptr_web_data = (char*) malloc((strlen(Data) + 1) * sizeof(char)); memcpy (ptr_web_data, column_text, strlen(column_text) + 1); qdat[row_index][web_data_index] = ptr_web_data; } } tdat[row_index] = qdat[col_index]; After the data is used, the memory allocated is released one at a time using free(). for(row_index = 0; row_index < number_rows; row_index++) { // Loop thru all columns used for(col_index = 0; col_index < SARWEBTBLCOLS; col_index++) { // Free memory block pointed to by results set array free(tdat[row_index][col_index]); } } Is there a way to release all the allocated memory at once, for this array? Thank You.

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  • An array of LPWSTR pointers, not working right.

    - by BigBirdy
    Declare: LPWSTR** lines= new LPWSTR*[totalLines]; then i set using: lines[totalLines]=&totalText; SetWindowText(totalChat,(LPWSTR)lines[totalLines]); totalLines++; Now I know totalText is right, cause if i SetWindowText using totalText it works fine. I need the text in totalLines too. I'm also doing: //accolating more memory. int orgSize=size; LPWSTR** tempArray; if (totalLines == size) { size *= 2; tempArray = new LPWSTR*[size]; memcpy(tempArray, lines,sizeof(LPWSTR)*orgSize); delete [] lines; lines = tempArray; } to allocate more memory when needed. My problem is that the lines is not getting the right data. It works for the first time around then it get corrupted. I thought at first i was overwriting but totalLines is increase. Hopefully this is enough information.

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  • NSCFString leak inVolving NSString

    - by Srilakshmi Manthena
    Hi, I am getting leak at NSString *firstNameStr = [NSString stringWithFormat:@"%s",firstNameString]; CODE: +(NSString *)getValueForProperty:(ABPropertyID)propertyId forContact:(NSString *)contactId { if (addressBook == nil) { addressBook = ABAddressBookCreate(); } ABRecordID contactIntId = [contactId intValue]; ABRecordRef person = ABAddressBookGetPersonWithRecordID(addressBook, contactIntId); CFStringRef firstName; char *firstNameString; firstName = ABRecordCopyValue(person, propertyId); // Paso a char* los datos para que se puedan escribir static char* fallback = ""; int fbLength = strlen(fallback); int firstNameLength = fbLength; bool firstNameFallback = true; if (firstName != NULL) { firstNameLength = (int) CFStringGetLength(firstName); firstNameFallback = false; } if (firstNameLength == 0) { firstNameLength = fbLength; firstNameFallback = true; } firstNameString = malloc(sizeof(char)*(firstNameLength+1)); if (firstNameFallback == true) { strcpy(firstNameString, fallback); } else { CFStringGetCString(firstName, firstNameString, 10*CFStringGetLength(firstName), kCFStringEncodingASCII); } if (firstName != NULL) { CFRelease(firstName); } NSString *firstNameStr = [NSString stringWithFormat:@"%s",firstNameString]; free(firstNameString); return firstNameStr; }

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  • Pointers to structs

    - by Bobby
    I have the following struct: struct Datastore_T { Partition_Datastores_T cmtDatastores; // bytes 0 to 499 Partition_Datastores_T cdhDatastores; // bytes 500 to 999 Partition_Datastores_T gncDatastores; // bytes 1000 to 1499 Partition_Datastores_T inpDatastores; // bytes 1500 1999 Partition_Datastores_T outDatastores; // bytes 2000 to 2499 Partition_Datastores_T tmlDatastores; // bytes 2500 to 2999 Partition_Datastores_T sm_Datastores; // bytes 3000 to 3499 }; I want to set a char* to struct of this type like so: struct Datastore_T datastores; // Elided: datastores is initialized with data here char* DatastoreStartAddr = (char*)&datastores; memset(DatastoreStartAddr, 0, sizeof(Datastore_T)); The problem I have is that the value that DatastoreStartAddr points to always has a value of zero when it should point to the struct that has been initialized with data. Meaning if I change the values in the struct using the struct directly, the values pointed to by DatastoreStartAddr should also change b/c they are pointing to the same address. But this is not happening. What am I doing wrong?

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  • Dangling pointers and double free

    - by user151410
    After some painful experiences, I understand the problem of dangling pointers and double free. I am seeking proper solutions. aStruct has a number of fields including other arrays. aStruct *A=NULL, *B = NULL; A = (aStruct*) calloc(1, sizeof(sStruct)); B = A; free_aStruct(A); ... //bunch of other code in various places. ... free_aStruct(B); Is there any way to write free_aStruct(X) so that free_aStruct(B) exists gracefully?? void free_aStruct(aStruct *X){ if (X ! = NULL){ if (X->a != NULL){free(X->a); x->a = NULL;} free(X); X = NULL; } } Doing above only sets A = NULL when free_aStruct(A); is called. B is now dangling. How can this situation be avoided / remedied? Is reference counting the only viable solution? or, are there other "defensive" free approaches, to prevent free_aStruct(B); from exploding? Thanks, Russ

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  • How to start writing out an existing AudioQueue in response to an event?

    - by Halle
    Hello, I am writing a class that opens an AudioQueue and analyzes its characteristics, and then under certain conditions can begin or end writing out a file from that AudioQueue that is already instantiated. This is my code (entirely based on SpeakHere) that opens the AudioQueue without writing anything out to tmp: void AQRecorder::StartListen() { int i, bufferByteSize; UInt32 size; try { SetupAudioFormat(kAudioFormatLinearPCM); XThrowIfError(AudioQueueNewInput(&mRecordFormat, MyInputBufferHandler, this, NULL, NULL, 0, &mQueue), "AudioQueueNewInput failed"); mRecordPacket = 0; size = sizeof(mRecordFormat); XThrowIfError(AudioQueueGetProperty(mQueue, kAudioQueueProperty_StreamDescription, &mRecordFormat, &size), "couldn't get queue's format"); bufferByteSize = ComputeRecordBufferSize(&mRecordFormat, kBufferDurationSeconds); for (i = 0; i < kNumberRecordBuffers; ++i) { XThrowIfError(AudioQueueAllocateBuffer(mQueue, bufferByteSize, &mBuffers[i]), "AudioQueueAllocateBuffer failed"); XThrowIfError(AudioQueueEnqueueBuffer(mQueue, mBuffers[i], 0, NULL), "AudioQueueEnqueueBuffer failed"); } mIsRunning = true; XThrowIfError(AudioQueueStart(mQueue, NULL), "AudioQueueStart failed"); } catch (CAXException &e) { char buf[256]; fprintf(stderr, "Error: %s (%s)\n", e.mOperation, e.FormatError(buf)); } catch (...) { fprintf(stderr, "An unknown error occurred\n"); } } But I'm a little unclear on how to write a function that will tell this queue "from now until the stop signal, start writing out this queue to tmp as a file". I understand how to tell an AudioQueue to write out as a file at the time that it's created, how to set files format, etc, but not how to tell it to start and stop midstream. Much appreciative of any pointers, thanks.

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  • What is a NULL value

    - by Adi
    I am wondering , what exactly is stored in the memory when we say a particular variable pointer to be NULL. suppose I have a structure, say typdef struct MEM_LIST MEM_INSTANCE; struct MEM_LIST { char *start_addr; int size; MEM_INSTANCE *next; }; MEM_INSTANCE *front; front = (MEM_INSTANCE*)malloc(sizeof(MEM_INSTANCE*)); -1) If I make front=NULL. What will be the value which actually gets stored in the different fields of the front, say front-size ,front-start_addr. Is it 0 or something else. I have limited knowledge in this NULL thing. -2) If I do a free(front); It frees the memory which is pointed out by front. So what exactly free means here, does it make it NULL or make it all 0. -3) What can be a good strategy to deal with initialization of pointers and freeing them . Thanks in advance

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  • Declaration, allocation and assignment of an array of pointers to function pointers

    - by manneorama
    Hello Stack Overflow! This is my first post, so please be gentle. I've been playing around with C from time to time in the past. Now I've gotten to the point where I've started a real project (a 2D graphics engine using SDL, but that's irrelevant for the question), to be able to say that I have some real C experience. Yesterday, while working on the event system, I ran into a problem which I couldn't solve. There's this typedef, //the void parameter is really an SDL_Event*. //but that is irrelevant for this question. typedef void (*event_callback)(void); which specifies the signature of a function to be called on engine events. I want to be able to support multiple event_callbacks, so an array of these callbacks would be an idea, but do not want to limit the amount of callbacks, so I need some sort of dynamic allocation. This is where the problem arose. My first attempt went like this: //initial size of callback vector static const int initial_vecsize = 32; //our event callback vector static event_callback* vec = 0; //size static unsigned int vecsize = 0; void register_event_callback(event_callback func) { if (!vec) __engine_allocate_vec(vec); vec[vecsize++] = func; //error here! } static void __engine_allocate_vec(engine_callback* vec) { vec = (engine_callback*) malloc(sizeof(engine_callback*) * initial_vecsize); } First of all, I have omitted some error checking as well as the code that reallocates the callback vector when the number of callbacks exceed the vector size. However, when I run this code, the program crashes as described in the code. I'm guessing segmentation fault but I can't be sure since no output is given. I'm also guessing that the error comes from a somewhat flawed understanding on how to declare and allocate an array of pointers to function pointers. Please Stack Overflow, guide me.

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  • va_arg with pointers

    - by Yktula
    I want to initialize a linked list with pointer arguments like so: /* * Initialize a linked list using variadic arguments * Returns the number of structures initialized */ int init_structures(struct structure *first, ...) { struct structure *s; unsigned int count = 0; va_list va; va_start(va, first); for (s = first; s != NULL; s = va_arg(va, (struct structure *))) { if ((s = malloc(sizeof(struct structure))) == NULL) { perror("malloc"); exit(EXIT_FAILURE); } count++; } va_end(va); return count; } The problem is that clang errors type name requires a specifier or qualifier at va_arg(va, (struct structure *)), and says that the type specifier defaults to int. It also notes instantiated form at (struct structure *) and struct structure *. This, what seems to be getting assigned to s is int (struct structure *). It compiles fine when parentheses are removed from (struct structure *), but the structures that are supposed to be initialized are inaccessible. Why is int assumed when parentheses are around the type argument passed to va_arg? How can I fix this?

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  • Incompatible types when assigning to type 'struct compartido'

    - by user1660559
    I have one problem with this code. I should create one structure and share it across 5 new process created from the father: #include <stdio.h> #include <stdlib.h> #include <sys/wait.h> #include <unistd.h> #include <sys/types.h> #include <sys/ipc.h> #include <sys/shm.h> #include <sys/sem.h> #include <time.h> struct compartido { int pid1, pid2, pid3, pid4, pid5; int propietario; int contador; int pidpadre; }; struct compartido var; int main(int argc, char *argv[]) { key_t llave1,llavesem; int idmem,idsem; llave1=ftok("/tmp",'a'); idmem=shmget(llave1,sizeof(int),IPC_CREAT|0600); if (idmem==-1) { perror ("shmget"); return 1; } var=shmat(idmem,0,0); /*This line is giving the error*/ /*rest of the code*/ } The exact error is giving is: error: incompatible types when assigning to type 'struct compartido' from type 'void *' I need to put this structure in the shared variable to be able to see and modify all those data from the 6 process (5 children and the father). What I'm doing bad? Thanks in advance and best regards,

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  • A good solution for displaying galleries with lytebox and php

    - by Johann
    Hello I have thought for a while over an issue with the loading of images on a website-solution that I have programmed (For fun and the experience) The programming language used is PHP with MYSQL as the database language It also uses javascript, but not extensively I have recently realized that the engine I programmed, while it has it's smart solutions also carry a lot of flaws and redundant code. I have therefore decided to make a new one, now incorporating what I know, but didn't when I started the previous project. For the new system, there will be an option to add galleries to a site, and upload images to it. I have used the javascript image viewer Lytebox before. The screen goes dark and an image appears with a "Previous" and "next" button to view the other images. The problem is that I used groups with lytebox and the images themselves, resized as thumbs. This causes lytebox to work only when all the images have loaded. If you click a link before that, the image is shown as if you right click and choose "Show image" Information about these images is parsed from a database using a while statement with a counter that goes from 0 to sizeof() I'm thinking it probably isn't a good idea to have the images as the thumbs, even if you restrict the upload size. Likewise, adding thumbs at upload also seems like a hassle. It would be practical if the thumbs didn't show up before they were fully loaded. Has anyone got any good tips. Any help would be appreciated. Johann

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  • Linked list example using threads

    - by Carl_1789
    I have read the following code of using CRITICAL_SECTION when working with multiple threads to grow a linked list. what would be the main() part which uses two threads to add to linked list? #include <windows.h> typedef struct _Node { struct _Node *next; int data; } Node; typedef struct _List { Node *head; CRITICAL_SECTION critical_sec; } List; List *CreateList() { List *pList = (List*)malloc(sizeof(pList)); pList->head = NULL; InitializeCriticalSection(&pList->critical_sec); return pList; } void AddHead(List *pList, Node *node) { EnterCriticalSection(&pList->critical_sec); node->next = pList->head; pList->head = node; LeaveCriticalSection(&pList->critical_sec); } void Insert(List *pList, Node *afterNode, Node *newNode) { EnterCriticalSection(&pList->critical_sec); if (afterNode == NULL) { AddHead(pList, newNode); } else { newNode->next = afterNode->next; afterNode->next = newNode; } LeaveCriticalSection(&pList->critical_sec); } Node *Next(List *pList, Node *node) { Node* next; EnterCriticalSection(&pList->critical_sec); next = node->next; LeaveCriticalSection(&pList->critical_sec); return next; }

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  • How can I obtain the local TCP port and IP Address of my client program?

    - by Dr Dork
    Hello! I'm prepping for a simple work project and am trying to familiarize myself with the basics of socket programming in a Unix dev environment. At this point, I have some basic server side code and client side code setup to communicate. Currently, my client code successfully connects to the server code and the server code sends it a test message, then both quit out. Perfect! That's exactly what I wanted to accomplish. Now I'm playing around with the functions used to obtain info about the two environments (server and client). I'd like to obtain the local IP address and dynamically assigned TCP port of the client. The function I've found to do this is getsockname()... //setup the socket if ((sockfd = socket(p->ai_family, p->ai_socktype, p->ai_protocol)) == -1) { perror("client: socket"); continue; } //Retrieve the locally-bound name of the specified socket and store it in the sockaddr structure sa_len = sizeof(sa); getsock_check = getsockname(sockfd,(struct sockaddr *)&sa,(socklen_t *)&sa_len) ; if (getsock_check== -1) { perror("getsockname"); exit(1); } printf("Local IP address is: %s\n", inet_ntoa(sa.sin_addr)); printf("Local port is: %d\n", (int) ntohs(sa.sin_port)); but the output is always zero... Local IP address is: 0.0.0.0 Local port is: 0 does anyone see anything I might be or am definitely doing wrong? Thanks so much in advance for all your help!

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  • pthread_exit and/or pthread_join causing Abort and SegFaults.

    - by MJewkes
    The following code is a simple thread game, that switches between threads causing the timer to decrease. It works fine for 3 threads, causes and Abort(core dumped) for 4 threads, and causes a seg fault for 5 or more threads. Anyone have any idea why this might be happening? #include <stdio.h> #include <stdlib.h> #include <pthread.h> #include <errno.h> #include <assert.h> int volatile num_of_threads; int volatile time_per_round; int volatile time_left; int volatile turn_id; int volatile thread_running; int volatile can_check; void * player (void * id_in){ int id= (int)id_in; while(1){ if(can_check){ if (time_left<=0){ break; } can_check=0; if(thread_running){ if(turn_id==id-1){ turn_id=random()%num_of_threads; time_left--; } } can_check=1; } } pthread_exit(NULL); } int main(int argc, char *args[]){ int i; int buffer; pthread_t * threads =(pthread_t *)malloc(num_of_threads*sizeof(pthread_t)); thread_running=0; num_of_threads=atoi(args[1]); can_check=0; time_per_round = atoi(args[2]); time_left=time_per_round; srandom(time(NULL)); //Create Threads for (i=0;i<num_of_threads;i++){ do{ buffer=pthread_create(&threads[i],NULL,player,(void *)(i+1)); }while(buffer == EAGAIN); } can_check=1; time_left=time_per_round; turn_id=random()%num_of_threads; thread_running=1; for (i=0;i<num_of_threads;i++){ assert(!pthread_join(threads[i], NULL)); } return 0; }

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  • How can I render an in-memory UIViewController's view Landscape?

    - by Aaron
    I'm trying to render an in-memory (but not in hierarchy, yet) UIViewController's view into an in-memory image buffer so I can do some interesting transition animations. However, when I render the UIViewController's view into that buffer, it is always rendering as though the controller is in Portrait orientation, no matter the orientation of the rest of the app. How do I clue this controller in? My code in RootViewController looks like this: MyUIViewController* controller = [[MyUIViewController alloc] init]; int width = self.view.frame.size.width; int height = self.view.frame.size.height; int bitmapBytesPerRow = width * 4; unsigned char *offscreenData = calloc(bitmapBytesPerRow * height, sizeof(unsigned char)); CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); CGContextRef offscreenContext = CGBitmapContextCreate(offscreenData, width, height, 8, bitmapBytesPerRow, colorSpace, kCGImageAlphaPremultipliedLast); CGContextTranslateCTM(offscreenContext, 0.0f, height); CGContextScaleCTM(offscreenContext, 1.0f, -1.0f); [(CALayer*)[controller.view layer] renderInContext:offscreenContext]; At that point, the offscreen memory buffers contents are portrait-oriented, even when the window is in landscape orientation. Ideas?

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  • Finding Local IP via Socket Creation / getsockname

    - by BSchlinker
    I need to get the IP address of a system within C++. I followed the logic and advice of another comment on here and created a socket and then utilized getsockname to determine the IP address which the socket is bound to. However, this doesn't appear to work (code below). I'm receiving an invalid IP address (58.etc) when I should be receiving a 128.etc Any ideas? string Routes::systemIP(){ // basic setup int sockfd; char str[INET_ADDRSTRLEN]; sockaddr* sa; socklen_t* sl; struct addrinfo hints, *servinfo, *p; int rv; memset(&hints, 0, sizeof hints); hints.ai_family = AF_UNSPEC; hints.ai_socktype = SOCK_DGRAM; if ((rv = getaddrinfo("4.2.2.1", "80", &hints, &servinfo)) != 0) { fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rv)); return "1"; } // loop through all the results and make a socket for(p = servinfo; p != NULL; p = p->ai_next) { if ((sockfd = socket(p->ai_family, p->ai_socktype, p->ai_protocol)) == -1) { perror("talker: socket"); continue; } break; } if (p == NULL) { fprintf(stderr, "talker: failed to bind socket\n"); return "2"; } // get information on the local IP from the socket we created getsockname(sockfd, sa, sl); // convert the sockaddr to a sockaddr_in via casting struct sockaddr_in *sa_ipv4 = (struct sockaddr_in *)sa; // get the IP from the sockaddr_in and print it inet_ntop(AF_INET, &(sa_ipv4->sin_addr.s_addr), str, INET_ADDRSTRLEN); printf("%s\n", str); // return the IP return str; }

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  • Is there a good way to copy a Gtk widget?

    - by Jake
    Is there a way, using the Gtk library in C, to clone a Gtk button (for instance), and pack it somewhere else in the app. I know you can't pack the same widget twice. And that this code obviously wouldn't work, but shows what happens when I attempt a shallow copy of the button: GtkButton *a = g_object_new(GTK_TYPE_BUTTON, "label", "o_0", NULL); GtkButton *b = g_memdup(b, sizeof *b); gtk_box_pack_start_defaults(GTK_BOX(vbox), GTK_WIDGET(b)); There is surrounding code which creates a vbox and packs it in a window and runs gtk_main(). This will result in these hard to understand error messages: (main:6044): Gtk-CRITICAL **: gtk_widget_hide: assertion `GTK_IS_WIDGET (widget)' failed (main:6044): Gtk-CRITICAL **: gtk_widget_realize: assertion `GTK_WIDGET_ANCHORED (widget) || GTK_IS_INVISIBLE (widget)' failed ** Gtk:ERROR:/build/buildd/gtk+2.0-2.18.3/gtk/gtkwidget.c:8431:gtk_widget_real_map: assertion failed: (GTK_WIDGET_REALIZED (widget)) Along the same lines, if I were to write my own GObject (not necessarily a Gtk widget), is there a good way to write a copy constructor. Im thinking it should be an interface with optional hooks and based mostly on the properties, handling the class's hierarchy in some way. I'd want to do this: GtkButton *b = copyable_copy(COPYABLE(a)); If GtkButton could use a theoretical copyable interface.

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  • C standard addressing simplification inconsistency

    - by Chris Lutz
    Section §6.5.3.2 "Address and indirection operators" ¶3 says (relevant section only): The unary & operator returns the address of its operand. ... If the operand is the result of a unary * operator, neither that operator nor the & operator is evaluated and the result is as if both were omitted, except that the constraints on the operators still apply and the result is not an lvalue. Similarly, if the operand is the result of a [] operator, neither the & operator nor the unary * that is implied by the [] is evaluated and the result is as if the & operator were removed and the [] operator were changed to a + operator. ... This means that this: int *i = NULL; printf("%p", (void *) (&*i) ); printf("%p", (void *) (&i[10]) ); Should be perfectly legal, printing the null pointer (probably 0) and the null pointer plus 10 (probably 10). The standard seems very clear that both of those cases are required to be optimized. However, it doesn't seem to require the following to be optimized: struct { int a; short b; } *s = 0; printf("%p", (void *) (&s->b) ); This seems awfully inconsistent. I can see no reason that the above code shouldn't print the null pointer plus sizeof(int) (possibly 4). Simplifying a &-> expression is going to be the same conceptually (IMHO) as &[], a simple address-plus-offset. It's even an offset that's going to be determinable at compile time, rather than potentially runtime with the [] operator. Is there anything in the rationale about why this is so seemingly inconsistent?

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