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  • Increase a recive buffer in UDP socket

    - by unresolved_external
    I'wm writing an app, which transmits video and obviously uses UDP protocol fot this purpose. So I am wondering how can I increase a size of send/recieve buffer, cause currently the maximal size of data, which I can send is 65000 bytes. I already tried to do it in following way: int option = 262144; if(setsockopt(m_SocketHandle,SOL_SOCKET,SO_RCVBUF ,(char*)&option,sizeof(option)) < 0) { printf("setsockopt failed\n"); } But it did not work. So how can I do it?

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  • Boost ASIO read X bytes synchroniously into a vector

    - by xeross
    Hey, I've been attempting to write a client/server app with boost now, so far it sends and receives but I can't seem to just read X bytes into a vector. If I use the following code vector<uint8_t> buf; for (;;) { buf.resize(4); boost::system::error_code error; size_t len = socket.read_some(boost::asio::buffer(buf), error); if (error == boost::asio::error::eof) break; // Connection closed cleanly by peer. else if (error) throw boost::system::system_error(error); // Some other error. } And the packet is bigger then 4 bytes then it seems it keeps writing into those 4 bytes until the entire packet has been received, however I want it to fetch 4 bytes, then allow me to parse them, and then get the rest of the packet. Can anyone provide me with a working example, or at least a pointer on how to make it work properly ? Regards, Xeross

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  • HRESULT exception not caught in VS 2008

    - by arionik
    Hello all, I've got a stange situation in visual studio 2008 C++. I work on code that was originally written for visual studio 2003, where everything works well. Now, ported to VS 2008, the exception handling, which unfortuantely exists widely in the code, does not work anymore. standard code example: try { HRESULT hr = S_OK; // do stuff... if( FAILED( hr ) ) throw hr; } catch( HRESULT hr ) { // error handling, but we never get here } catch( ... ) { // ... not even here } Under VS 2008, no exception is encountered, but I get a crash somewhere else, indicating that the stack pointer must be screwed up. Did anybody come across this behaviour? Any help is appreciated.

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  • C++ iterators & loop optimization

    - by Quantum7
    I see a lot of c++ code that looks like this: for( const_iterator it = list.begin(), const_iterator ite = list.end(); it != ite; ++it) As opposed to the more concise version: for( const_iterator it = list.begin(); it != list.end(); ++it) Will there be any difference in speed between these two conventions? Naively the first will be slightly faster since list.end() is only called once. But since the iterator is const, it seems like the compiler will pull this test out of the loop, generating equivalent assembly for both.

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  • Can't subtract in a for loop in C/Objective-C

    - by user1612935
    I'm going through the Big Nerd Ranch book on Objective-C, which takes you through some early C stuff. I've played with C before, and am pretty experienced in PHP. Anyhow, I'm doing the challenges and this one is not working the way I think it should. It's pretty simple - start at 99, loop through and subtract three until you get to zero, and every time you get a number that is divisible by 5 print "Found one." Pretty straightforward. However, subtracting by three in the for loop is not working #include <stdio.h> int main (int argc, const char * argv[]) { int i; for(i = 99; i > 0; i-3){ printf("%d\n", i); if(i % 5 == 0) { printf("Found one!\n"); } } return 0; } It creates and endless loop at 99, and I'm not sure why.

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  • pointers in C with a #define

    - by milan
    The function: #define ASSOC(port) (*(volatile bit_field *) (&port)) The function call: #define SCLK ASSOC(PORTC).bit0 bit_field defined as a struct like this: typedef struct { unsigned char bit0 :1, bit1 :1, bit2 :1, bit3 :1, bit4 :1, bit5 :1, bit6 :1, bit7 :1; } bit_field; I don't know where &port is defined. Can someone please explain how the function is read and how it works please? I am not very good with pointers and this example in particular is very confusing with "*" in the front and at the end and the "&" with the port. Thank you

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  • C++, constructor restrictions

    - by Pie86
    Hi everybaody, I'm studing C++ and I can't understand the meaning of the boldface sentence below: From IBM manual: The following restrictions apply to constructors and destructors: Constructors and destructors do not have return types nor can they return values. References and pointers cannot be used on constructors and destructors because their addresses cannot be taken. Constructors cannot be declared with the keyword virtual. Constructors and destructors cannot be declared static, const, or volatile. Unions cannot contain class objects that have constructors or destructors. Could you please provide me an example? Thank you!

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  • Best way to access nested data structures?

    - by Blackshark
    I would like to know what the best way (performance wise) to access a large data structure is. There are about hundred ways to do it but what is the most accessible for the compiler to optimize? One can access a value by foo[someindex].bar[indexlist[i].subelement[j]].baz[0] or create some pointer aliases like sometype_t* tmpfoo = &foo[someindex]; tmpfoo->bar[indexlist[i].subelement[j]].baz[0] or create reference aliases like sometype_t &tmpfoo = foo[someindex]; tmpfoo.bar[indexlist[i].subelement[j]].baz[0] and so forth...

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  • Printing escape character

    - by danutenshu
    When I am given "d""\"/""b", I need to print out the statement character for character. (d, b, a slash, a backslash, and 5 quotes) in C++. The only errors that show now are the lines if(i.at(j)="\\") and else if(i.at(j)="\""). Also, how should the outside double apostrophes be excluded? #include <iostream> #include <cstdlib> using namespace std; int main (int argc, const char* argv[] ) { string i= argv[1]; for (int j=0; j>=sizeof(i)-1; j++) { if(i.at(j)="\\") { cout << "\\"; } else if(i.at(j)="\"") { cout << "\""; } else { cout << i.at(j); } } return 0; }

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  • SetWindowLongPtr with DialogBoxParam?

    - by templatetypedef
    Hey all- A while back I was writing a C++ program with the Win32 API that would display a dialog box and then listen to the messages it generated. At one point, I was interested in associating a piece of data with the dialog window. Were I manually creating the window and attaching a window proc, I'd just use SetWindowLongPtr to set the GWLP_USERDATA field to a pointer to the data to associate. However, in this case I was creating and displaying the window with DialogBoxParam, and it wasn't clear whether this function was associating that data with its own internal state. Since the MSDN didn't have a description of what would happen in this case, I ended up using some other approach to solve the problem. My question is this - is it safe to use SetWindowLongPtr to overwrite the GWLP_USERDATA value in a window created by DialogBoxParam? Thanks!

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  • Read text and print each (byte) character in separate line

    - by user2967663
    preforming this code to read file and print each character \ (byte) in separate line works well with ASCII void preprocess_file (FILE *fp) { int cc; for (;;) { cc = getc (fp); if (cc == EOF) break; printf ("%c\n", cc); } } int main(int argc, char *argv []) { preprocess_file (stdin); exit (0); } but when i use it with UTF-8 encoded text it shows unredable character such as ï » ? ? § ? „ ? … ? ¤ ? ´ ? and advice ? Thanks

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  • HTML5 placing image where i want it on screen

    - by corrigan_sam
    I have a little start screen running and i want the image, which is acting as a button, to placed at a certain point, but when i try to it stays in the same place, and i don't know how i can get it to stay in the place i want it. Here is my code, its is HTML with some css: <style> #SplashScreen{ position:relative; overflow:hidden; } #StartButton { cursor:pointer; position:absoloute; left:100px; top:100px; } </style> <div id="SplashScreen" width="400" height="400"> <h1>Game Title</h1> <img id="StartButton" src="play.png"/> </div> The image just draws underneath the title and not where i want it. Any help?

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  • How to create a Mutex with security attribute to share resource from different application?

    - by Antony Tess
    How to create a Mutex with security attribute rigth to share resource from different application? In according with Microsoft SDK documentation the CreateMutex API accept as first parameter a SECURITY_ATTRIBUTES pointer. HANDLE WINAPI CreateMutex( __in LPSECURITY_ATTRIBUTES lpMutexAttributes, __in BOOL bInitialOwner, __in LPCTSTR lpName ); I want to create the rigth security attribute so only my application group can open the MUTEX and access to a specific resource (a file) where my application gruop read/write data operation. The target opertaing system are XP, Vista and Seven. The feature must working in both, administrator/standard user, login shenario.

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  • string holding text every \n

    - by gcc
    I tried to take input in form of string, specifically: int i=0; char c[50][500]; for(;i<50;++i) scanf("%s",A[i]); The input is x is a website that allows the easy[1] creation and editing of any number of interlinked web pages via a web browser using a simplified markup language or a WYSIWYG text editor. In my program, I want the text to be stored as: A[0]="x is a website that allows the easy[1] creation and editing of any number of interlinked" A[1]=" web pages via a web browser using a simplified markup language or a WYSIWYG text editor." But my code causes the text to be stored as A[0]="is" A[1]="a" A[2]="website" .... What am I doing wrong?

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  • .net equivalent for php preg_replace

    - by Hath
    What is the c#.net equivalent for php's preg_replace function? php code is like this: const ALLOW_VALUES = '[^a-z0-9àáâäèéêëìíîïòóôöùûwýÿyÁÂÄÈÉÊËÌÎÏÒÓÔÖÙÛÜWYÝ]'; public function streetTownHash($data, $hashCheck = false, $updateRecord = false) { foreach($data as $key=>$value){ try{ $value = mb_convert_case($value, MB_CASE_LOWER, "UTF-8"); } catch(Exception $e) { echo "Requires extension=php_mbstring.dll enabled ! - $e"; } $valueConcat .= preg_replace('/'.self::ALLOW_VALUES.'/','',$value); # Remove punctuation etc } $streetTownHash = sha1($valueConcat); .... this is as far as i've got but not sure about it.. private SHA1 hash = SHA1.Create(); private string hashAllowed = "[^a-z0-9àáâäèéêëìíîïòóôöùûwýÿyÁÂÄÈÉÊËÌÎÏÒÓÔÖÙÛÜWYÝ]"; public string HashString(string value) { value = // = regex not sure this part var bytes = ASCIIEncoding.UTF8.GetBytes(value); var hashed = hash.ComputeHash(bytes); return ASCIIEncoding.UTF8.GetString(hashed); }

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  • Force to reimplement a static function in inherit classes

    - by pacopepe
    Hi, I have a program in C++ with plugins (dynamic libs). In the main program, I want to execute a static function to check if i can create a object of this type. An example without dynamic libs (aren't neccesary to understand the problem): #include "libs/parent.h" #include "libs/one.h" #include "libs/two.h" int main(int argc, char * argv[]) { Parent obj; if (One.match(argv[1])) { obj = new One(); else if (Two.match(argv[1])) { obj = new Two(); } Now, i have a interface class named Parent. All plugins inherit from this class. Ideally, I have a virtual static function in Parent named match, and all the plugins need to reimplement this function. The problem with this code is that i can't do a static virtual function in C++, so i don't know how to solve the problem. Sorry for mi english, i did my best

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  • C++ toLowerCase Function won't work - Access violation

    - by misaizdaleka
    Hi, I have a simple function which takes an array of characters as an argument, and converts all the characters to lower case. However, I get a weird access violation error. Here's the code: void toLower(char *rec) { int i=0; while (rec[i]!='\0') { if (rec[i]>='A' && rec[i]<='Z') rec[i]='a'+rec[i]-'A'; //this is where I get an error - assigning the //the value to rec[i] is the problem i++; } } Can you tell me what's my mistake? Thanks

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  • Why does a non-constant offsetof expression work?

    - by Chris J. Kiick
    Why does this work: #include <sys/types.h> #include <stdio.h> #include <stddef.h> typedef struct x { int a; int b[128]; } x_t; int function(int i) { size_t a; a = offsetof(x_t, b[i]); return a; } int main(int argc, char **argv) { printf("%d\n", function(atoi(argv[1]))); } If I remember the definition of offsetof correctly, it's a compile time construct. Using 'i' as the array index results in a non-constant expression. I don't understand how the compiler can evaluate the expression at compile time. Why isn't this flagged as an error?

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  • what's the meaning of ~0 in cpp or c

    - by rima
    Hi what's the meaning of ~0 in this code???? somebody can analysis this code for me? unsigned int Order(unsigned int maxPeriod = ~0) const { Point r = *this; unsigned int n = 0; while( r.x_ != 0 && r.y_ != 0 ) { ++n; r += *this; if ( n > maxPeriod ) break; } return n; } please help me soon....

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  • You have an error in your SQL syntax; check the manual that corresponds to your MySQL

    - by LuisEValencia
    I am trying to run a mysql query to find all occurences of a text. I have a syntax error but dont know where or how to fix it I am using sqlyog to execute this script DECLARE @url VARCHAR(255) SET @url = '1720' SELECT 'select * from ' + RTRIM(tbl.name) + ' where ' + RTRIM(col.name) + ' like %' + RTRIM(@url) + '%' FROM sysobjects tbl INNER JOIN syscolumns col ON tbl.id = col.id AND col.xtype IN (167, 175, 231, 239) -- (n)char and (n)varchar, there may be others to include AND col.length > 30 -- arbitrary min length into which you might store a URL WHERE tbl.type = 'U' -- user defined table 1 queries executed, 0 success, 1 errors, 0 warnings Query: declare @url varchar(255) set @url = '1720' select 'select * from ' + rtrim(tbl.name) + ' where ' + rtrim(col.name) + ' like %' ... Error Code: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'declare @url varchar(255)

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  • Java: How to get Unicode name of a character (or its type category)?

    - by java.is.for.desktop
    Hello, everyone! The Character class in Java defines methods which check a given char argument for equality with certain Unicode chars or for belonging to some type category. These chars and type categories are named. As stated in given javadoc, examples for named chars are HORIZONTAL TABULATION, FORM FEED, ...; example for named type categories are SPACE_SEPARATOR, PARAGRAPH_SEPARATOR, ... However, being byte or int values instead of enums, the name of these types are "hidden" at runtime. So, is there a possibility to get characters' and/or type categories' names at runtime?

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  • In PHP can I check a boolean on a function call?

    - by Chris
    I have a function which checks the passed value and returns false or true, if false I want it to add something to an array. The code I've written is below. if(!check_input($_POST['username'])){ $errors[] = "Username"; } Right now it adds to my array anyway, regardless of what is entered in the form. Is the way I've written that the correct way to check if the return from check_input() is false? I've checked the function's logic by altering the returns to echoes and it's returning the correct value, I'm just not sure if I'm checking it wrong. I'd previously attempted to write it as $X=check_input etc, and then if(check_value == false) but that doesn't seem to give me the desired result either. Hmmm a quick pointer please!

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  • MySQL: host name universal change.

    - by ctrlShiftBryan
    I am making some updates to a php site which I did not design. I have a local copy of the site. At the top of each page there are settings for the host name for the db connection. Is there someway I can setup a pointer to the remote address. The address is 'mysqlhost' for example and I want that to point to 'mysql.myhost.com'. I tried creating a HOST record for mysqlhost pointing to the IP address it resolves to but that doesn't work. If I put 'mysql.myhost.com' in the connection it works. If I put that IP address it doesn't so that is probably why the HOST record idea doesn't work. Other than creating a local copy of the DB is there a quick way so that I don't have to modify each file in my dev environment and then again when I redeploy?

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  • Unit testing a functions whose purposes is side effects

    - by David
    How would you unit test do_int_to_string_conversion? #include <string> #include <iostream> void do_int_to_string_conversion(int i, std::string& s) { switch(i) { case 1: s="1"; break; case 2: s="2"; break; default: s ="Nix"; } std::cout << s << "\n"; } int main(int argc, char** argv){ std::string little_s; do_int_to_string_conversion(1, little_s); do_int_to_string_conversion(2, little_s); do_int_to_string_conversion(3, little_s); }

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