Search Results

Search found 10366 results on 415 pages for 'const char pointer'.

Page 309/415 | < Previous Page | 305 306 307 308 309 310 311 312 313 314 315 316  | Next Page >

• How to make this jpeg compression faster

  - by Richard Knop

  I am using OpenCV to compress binary images from a camera: vector<int> p; p.push_back(CV_IMWRITE_JPEG_QUALITY); p.push_back(75); // JPG quality vector<unsigned char> jpegBuf; cv::imencode(".jpg", fIplImageHeader, jpegBuf, p); The code above compresses a binary RGB image stored in fIplImageHeader to a JPEG image. For a 640*480 image it takes about 0.25 seconds to execute the five lines above. Is there any way I could make it faster? I really need to repeat the compression more than 4 times a second.

  Read the article

• How to execute unknown functions from dynamic load libraries?

  - by activenightly

  It's easy to load functions from dynamic libraries when you know this function in design time. just do something like this: int (*fn)(int); l0 = dlopen("./libfoo.so", RTLD_LAZY); if (!l0) { fprintf(stderr, "l0 %s\n", dlerror()); return 1; } fn = (int (*)(int))dlsym(l0, "foo"); if ((error = dlerror()) != NULL) { fprintf(stderr, "fn:%s\n", error); return 1; } x=(*fn)(y); ... How to execute library function when it's unknown in design time? In runtime you have a function name and array of arguments pointers and array of arguments sizes: char* fn_name="foo"; int foo_argc; void* foo_argv[]; int foo_argv_size[]; In scripting language it's a piece a cake task, but how to implement this nicely in c++?

  Read the article

• how to represent negative number to array of integers ?

  - by stdnoit

  I must convert string of 1324312321 to array of integers in java this is fine. I could use integer parseint and string substring method but how do I repesent -12312312 to my original array of integer.. the fact that - is a char / string and convert to array of integer would alter the value ( even though I convert - to integer-equivalent , it would change the rest of 12312312) it must be an array of integers and how should I convert negative numbers and still keeep the same value somehow reminding me of two complements trick but i dont think i need to go down to binary level in my program.. any other trick for doing this? thanks!

  Read the article

• using arrays to get best memory alignment and cache use, is it necessary?

  - by Alberto Toglia

  I'm all about performance these days cause I'm developing my first game engine. I'm no c++ expert but after some research I discovered the importance of the cache and the memory alignment. Basically what I found is that it is recommended to have memory well aligned specially if you need to access them together, for example in a loop. Now, In my project I'm doing my Game Object Manager, and I was thinking to have an array of GameObjects references. meaning I would have the actual memory of my objects one after the other. static const size_t MaxNumberGameObjects = 20; GameObject mGameObjects[MaxNumberGameObjects]; But, as I will be having a list of components per object -Component based design- (Mesh, RigidBody, Transformation, etc), will I be gaining something with the array at all? Anyway, I have seen some people just using a simple std::map for storing game objects. So what do you guys think? Am I better off using a pure component model?

  Read the article

• array loop not working correctly? c++

  - by igor

  Trying to count how many elements within the array are not equal to 0, is something set up wrong? I'd like to check all values in the array (it's a sudoku board) and then when all elements are "full" I need to return true. Is something off? bool boardFull(const Square board[BOARD_SIZE][BOARD_SIZE]) { int totalCount=0; for (int index1 = 0; index1 < BOARD_SIZE; index1++) for (int index2 = 0; index2 < BOARD_SIZE; index2++){ if(board[index1][index2].number!=0) totalCount++; } if(totalCount=81) return true; else return false;

  Read the article

• SQL SELECT using in() but excluding others.

  - by Pickledegg

  I have a table called 'countries' linked to another table 'networks' with a many to many relationship: countries countries_networks networks +-------------+----------+ +-------------+----------+ +-------------+---------------+ | Field | Type | | Field | Type | | Field | Type | +-------------+----------+ +-------------+----------+ +-------------+---------------+ | id | int(11) | | id | int(11) | | id | int(11) | | countryName | char(35) | | country_id | int(11) | | name | varchar(100) | +-------------+----------+ | network_id | int(11) | | description | varchar(255) | To retrieve all countries that have a network_id of 6 & 7, I just do the following: ( I could go further to use the networks.name but I know the countries_networks.network_id so i just use those to reduce SQL.) SELECT DISTINCT countryName FROM countries AS Country INNER JOIN countries_networks AS n ON Country.id = n.country_id WHERE n.network_id IN (6,7) This is fine, but I then want to retrieve the countries with a network_id of JUST 8, and no others. I'ver tried the following but its still returning networks with 6 & 7 in. Is it something to do with my JOIN? SELECT DISTINCT countryName FROM countries AS Country INNER JOIN countries_networks AS n ON Country.id = n.country_id WHERE n.network_id IN (8) AND n.network_id not IN(6,7) Thanks.

  Read the article

• Bug in malloc or mine?

  - by Martin

  Is this my bug or a bug/assertion fail in malloc itself? alloc.c:2451: sYSMALLOc: Assertion `(old_top == (((mbinptr) (((char *) &((av)-bins[((1) - 1) * 2])) - __builtin_offsetof (struct malloc_chunk, fd)))) && old_size == 0) || ((unsigned long) (old_size) = (unsigned long)((((__builtin_offsetof (struct malloc_chunk, fd_nextsize))+((2 * (sizeof(size_t))) - 1)) & ~((2 * (sizeof(size_t))) - 1))) && ((old_top)-size & 0x1) && ((unsigned long)old_end & pagemask) == 0)' failed. libstdc++6:amd64 4.7.2-2ubuntu1 gcc 4.7.2 ubuntu 12.10/64bit

  Read the article

• What is the best way to expose a callback API - C++

  - by rursw1

  Hi, I have a C++ library that should expose some system\ resource calls as callbacks from the linked application. For example: the interfacing application (which uses this library) can send socket management callback functions - send, receive, open, close etc., and the library will use this implementation in stead of the library's implementation. (This way enables the application to manage the sockets by itself, can be useful). This library has to expose also more callbacks, like, for example, a password validation, so I wonder if there is a preferred method to expose the callback sending option in one API. Something like: int AddCallbackFunc (int functionCallbackType, <generic function prototype>, <generic way to pass some additional arguments>) Then within my library I will assign the callback to the appropriate function pointer according to the functionCallbackType parameter. Is there any way to implement it in a generic way which will fit ANY function prototype and ANY additional arguments? Your help will be more than appreciated... Thanks!

  Read the article

• What is the logic behind defining macros inside a struct?

  - by systemsfault

  As apparent in the title, I'm questioning the reason behind defining the macros inside a struct. I frequently see this approach in network programming for instance following snippet: struct sniff_tcp { u_short th_sport; /* source port */ u_short th_dport; /* destination port */ tcp_seq th_seq; /* sequence number */ tcp_seq th_ack; /* acknowledgement number */ u_char th_offx2; /* data offset, rsvd */ #define TH_OFF(th) (((th)->th_offx2 & 0xf0) >> 4) u_char th_flags; #define TH_FIN 0x01 #define TH_SYN 0x02 #define TH_RST 0x04 #define TH_PUSH 0x08 #define TH_ACK 0x10 #define TH_URG 0x20 #define TH_ECE 0x40 #define TH_CWR 0x80 #define TH_FLAGS (TH_FIN|TH_SYN|TH_RST|TH_ACK|TH_URG|TH_ECE|TH_CWR) u_short th_win; /* window */ u_short th_sum; /* checksum */ u_short th_urp; /* urgent pointer */ }; This example is from sniffex.c code in tcpdump's web site. Is this for enhancing readability and making code clearer.

  Read the article

• Simple C++ container class that is thread-safe for writing

  - by conradlee

  I am writing a multi-threaded program using OpenMP in C++. At one point my program forks into many threads, each of which need to add "jobs" to some container that keeps track of all added jobs. Each job can just be a pointer to some object. Basically, I just need the add pointers to some container from several threads at the same time. Is there a simple solution that performs well? After some googling, I found that STL containers are not thread-safe. Some stackoverflow threads address this question, but none that forms a consensus on a simple solution.

  Read the article

• NOT replacing ? with letter guessed

  - by user3720541

  i need my code to replace the ? with the letter guessed. The ? needs to be replaced with a for only those to spots. The word in array is parameter. public static void replace(String[] wordOne, String blanks, char guess) { int i; blanks = wordOne[0]; for (i = 0; i < wordOne.length; i++) { for (int j = 0; j < wordOne[0].length(); j++) { blanks = blanks.replace(blanks.charAt(j), '?'); if (wordOne[0].charAt(i) == guess) { blanks = blanks.replace(blanks.charAt(i), guess); } } } System.out.println(blanks); } }

  Read the article

• Looking at the C++ new[] cookie. How portable is this code?

  - by carleeto

  I came up with this as a quick solution to a debugging problem - I have the pointer variable and its type, I know it points to an array of objects allocated on the heap, but I don't know how many. So I wrote this function to look at the cookie that stores the number of bytes when memory is allocated on the heap. template< typename T > int num_allocated_items( T *p ) { return *((int*)p-4)/sizeof(T); } //test #include <iostream> int main( int argc, char *argv[] ) { using std::cout; using std::endl; typedef long double testtype; testtype *p = new testtype[ 45 ]; //prints 45 std::cout<<"num allocated = "<<num_allocated_items<testtype>(p)<<std::endl; delete[] p; return 0; } I'd like to know just how portable this code is.

  Read the article

• DataSet binding problem

  - by Shaine

  I've got in-memory dataset with some table defined and I populate this table in a following way: for(...) ds.Fields.AddFieldsRow(++j, 0, heading, "Char", "", "", "Input", 0, "","",""); On the GUI I've got DataGridView bound to that table inside TabControl (bound through BindingSource). Very strange thing is happening: if I open tab pane with this grid and populate table with some data then I see changes in grid. On the other side if I'm at other tab, populate table, and then switch to tab with grid I've got following exception: "DataMember property 'Fields' cannot be found on the DataSource". In similar way I've got 2 tab panes with grid in each that are bound to the same datatable using different datasources and I open one of them, populate, see the changes, then switch to second tab and get crash. What am I missing?

  Read the article

• Event handling C# / Registering a callback

  - by Jeff Dahmer

  Events can only return void and recieve object sender/eventargs right? If so then craptastic.... how can I pass a function pointer to another obj, like: public bool ACallBackFunc(int n) { return n > 0; } public void RegisterCallback(Something s) { s.GiveCallBack(this.ACallBackFunc); } Something::GiveCallBack(Action? funcPtr) I tried using Action, but I need it to return some value and Actions can only return void. Also, we do not know what kind of a callback we will be recieving; it could return anything and have any params! Reflection will have to be used somehow I reckon.

  Read the article

• Best way to get a date in .NET?

  - by frenchie

  I'm getting a string back from my page and I want to make sure it's a date. This is what I have so far (it works) and I just want to know if this is the "best" way to do it. I'm using .NET 4. int TheMonth =0; int TheDay = 0; int TheYear = 0; DateTime NewDate; var TheIncomingParam = Request.Params.Get("__EVENTARGUMENT").ToString(); char[] TheBreak = { '/' }; string[] TheOutput = TheIncomingParam.Split(TheBreak); try { TheMonth = Convert.ToInt32(TheOutput[0]); } catch { } try { TheDay = Convert.ToInt32(TheOutput[1]); } catch { } try { TheYear = Convert.ToInt32(TheOutput[2]); } catch { } if (TheMonth!=0 && TheDay!=0 && TheYear!=0) { try { NewDate = new DateTime(TheYear, TheMonth, TheDay); } catch { var NoDate = true; } }

  Read the article

• why it is up to the compiler to decide what value to assign when assigning an out-of-range value to

  - by Allopen

  in C++ Primer 4th edition 2.1.1, it says "when assigning an out-of-range value to a signed type, it is up to the compiler to decide what value to assign". I can't understand it. I mean, if you have code like "char 5 = 299", certainly the compiler will generate asm code like "mov BYTE PTR _sc$[ebp], 43"(VC) or "movb $43, -2(%ebp)"(gcc+mingw), it IS decided by the compiler. but what if we assign a value that is given by the user input? like, via command line? and the asm code generated will be "movb %al, -1(%ebp)"(gcc+mingw) and " mov cl, BYTE PTR _i$[ebp] mov BYTE PTR _sc$[ebp], cl "(VC), so now how can compiler decide what will happen? I think now it is decided by the CPU. Can you give me a clear explanation?

  Read the article

• C++, WCHAR[] to std::cout and comparision

  - by michal

  Hi, I need to put WCHAR[] to std::cout ... It is a part of PWLAN_CONNECTION_NOTIFICATION_DATA passed from Native Wifi API callback. I tried simply std::cout << var; but it prints out the numeric address of first char. the comparision (var == L"some text") doesn't work either. The debugger returns the expected value, however the comparision returns 0. How can I convert this array to a standard string(std::string)? Thanks in advance

  Read the article

• How to get "printer ready bytes" from a source in c#?

  - by luis_villase

  Hey everyone! I'm in a bit of trouble here, hoping you can help a fellow programmer out. I have an application that receives a pointer to raw bytes (plus length and stuff) and sends said raw data to a printer. This is important, I have no choice but to use this method to get any printing done. If I send a raw string, it will print with no problem. However, I need to be able to print formatted text, images, etc. So the thing is... I would like to be able to get printer ready bytes from a given source (maybe a pdf, or html, does not matter as long as it contains formatted text and/or images). It would be like "splitting" the print command like so: a) Open file and read data b) Load printer data into memory c) Send bytes to printer Obviously, I've got a) and c) covered, it's b) the one that's breaking my head. Any thoughts? Thanks in advance for your help.

  Read the article

• Iterating through std queue

  - by Ockonal

  Hi, I'm trying to use BOOST_FOREACH for iterating through the std::queue. But there isn't iterators in that class cause I have an error: std::queue<std::string> someList; BOOST_FOREACH(std::string temp, someList) { std::cout << temp; } >no matching function for call to begin(...) >no type named ‘iterator’ in ‘class std::queue<std::basic_string<char> >’ I need in structure like: the first comes, the first goes away.

  Read the article

• C++ inheritance question

  - by user233973

  Hi guys, I have a C++ inheritance related question. I have a set of classes like this (I have not given the complete class structure coz I am lazy :) ). I want to access chiComponent class public methods using com pointer. How should I go about it? Note that I am having to change the object which "com" is pointing to in a lot of places. So I do not think I can have another chiComponent *ccom = <some_cast> com; ccom.chiComponentMethod() How should I go about it? class Component{ }; class chiComponent : public Component { public: void chiComponentMethod() { cout << "Hi! Chi component function called!!"; } } class parent { protected: Component *com; }; class child : public parent{ public: child() { com = new chiComponent(); } } Regards Arun

  Read the article

• Single C++/CLI method to wrap many type specific C functions

  - by T33C

  I am wrapping a C library using C++/CLI so that the C library can be used easily from C# in a C#'ish way. Some of the functions in this library are for putting a value into a container. There are no generics in C so there exists a function per type CLIB_SetBool(BOOL value), CLIB_SetInt(int value), CLIB_SetString(char* string) and so on. To make it easier to use from C#, I have created a single Set function which takes a System::Object. I have two related questions: With my method how would you use a switch statement on the type of System::Object to call the correct CLIB_Setxxxx function. [typeid is only for unmanaged code and I can't seem to use GetType.] Is there a better way to wrap these functions like using a Generic? [I started using template specialisation but then realised that C# doesn't see templates.] Thanks.

  Read the article

• std::out_of_range error?

  - by vette982

  I'm dealing with a file with a linked list of lines with each node looking like this: struct TextLine{ //The actual text string text; //The line number of the document int line_num; //A pointer to the next line TextLine * next; }; and I'm writing a function that adds spaces at the beginning of the lines found in the variable text, by calling functions like linelist_ptr->text.insert(0,1,'\t'); The program compiles, but when I run it I get this error: terminate called after throwing an instance of 'std::out_of_range' what(): basic_string::at Aborted Any ideas?

  Read the article

• Is call to function object inlined?

  - by dehmann

  In the following code, Foo::add calls a function via a function object: struct Plus { inline int operator()(int x, int y) const { return x + y; } }; template<class Fct> struct Foo { Fct fct; Foo(Fct f) : fct(f) {} inline int add(int x, int y) { return fct(x,y); // same efficiency adding directly? } }; Is this the same efficiency as calling x+y directly in Foo::add? In other words, does the compiler typically directly replace fct(x,y) with the actual call, inlining the code, when compiling with optimizations enabled?

  Read the article

• memset on array of structures in C++

  - by garry

  I have another memset question. It appears as if the code I am editing may have some issues (or it's not done the same way in different files) A::LRM las[9]; //A and LRM are both structures with BOOLS and INTS memset(&las, 0, sizeof(las)); typedef Sec SecArray[16]; SecArray rad_array; memset(rad_array, 0, sizeof(SecArray)); The second example appears to be correct because rad_array is the same as the first position in the array. Then the sizeof(SecArray)) would make sense. The first one doesn't seem correct to me. All structs are just BOOLs and INTS nothing dynamic in them. My understanding from my other post about memset was that it followed this format. memset("pointer to object", "what to set it to", "size of object") Can anyone tell me what exactly is going on here if I am incorrect with my theory.

  Read the article

• View is moved 3 pixels

  - by Jakub

  Hello, In my app I move the table view (in order to make the text fields visible when the keyboard appears). The view is looks following: This is the code I use for resizing the view and moving it up: static const NSUInteger navBarHeight = 44; CGRect appFrame = [[UIScreen mainScreen] applicationFrame]; tableView.frame = CGRectMake(0, navBarHeight, appFrame.size.width, appFrame.size.height-navBarHeight-216); //216 for the keyboard NSIndexPath *indPath = [self getIndexPathForTextField:textField]; //get the field the view should scroll to [tableView scrollToRowAtIndexPath:indPath atScrollPosition:UITableViewScrollPositionMiddle animated:YES]; The problem is that when the view is moved up it also moves 3 pixels into right direction (it is hard to see the difference in the screenshot, but it is visible when the animation is on and I measured the difference with PixelStick tool). Here it is how it looks after the move: My analysis shows that scrolling the table does not influence the move to the right. Any ideas what is wrong in the code above that makes the view move to the right?

  Read the article

< Previous Page | 305 306 307 308 309 310 311 312 313 314 315 316  | Next Page >