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  • Introduction to midi programming

    - by bobobobo
    So I have a little (musical) keyboard that has USB midi interface. I know you can program to this (many programs accept input from the midi device via USB interface) but where do you begin to program a midi device? Ideally I'm looking for a platform-independent api, through Python or something.

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  • c programming malloc question

    - by user535256
    Hello guys, Just got query regarding c malloc() function. I am read()ing x number of bytes from a file to get lenght of filename, like ' read(file, &namelen, sizeof(unsigned char)); ' . The variable namelen is a type unsigned char and was written into file as that type (1 byte). Now namelen has the lenght of filename ie namelen=8 if file name was 'data.txt', plus extra /0 at end, that working fine. Now I have a structure recording file info, ie filename, filelenght, content size etc. struct fileinfo { char *name; ...... other variable like size etc }; struct fileinfo *files; Question: I want to make that files.name variable the size of namelen ie 8 so I can successfully write the filename into it, like ' files[i].name = malloc(namelen) ' However, I dont want it to be malloc(sizeof(namelen)) as that would make it file.name[1] as the size of its type unsigned char. I want it to be the value thats stored inside variable &namelen ie 8 so file.name[8] so data.txt can be read() from file as 8 bytes and written straight into file.name[8? Is there a way to do this my current code is this and returns 4 not 8 files[i].name = malloc(namelen); //strlen(files[i].name) - returns 4 //perhaps something like malloc(sizeof(&namelen)) but does not work Thanks for any suggestions Have tried suggested suggestions guys, but I now get a segmentation fault error using: printf("\nsizeofnamelen=%x\n",namelen); //gives 8 for data.txt files[i].name = malloc(namelen + 1); read(file, &files[i].name, namelen); int len=strlen(files[i].name); printf("\nnamelen=%d",len); printf("\nname=%s\n",files[i].name); When I try to open() file with that files[i].name variable it wont open so the data does not appear to be getting written inside the read() &files[i].name and strlen() causes segemntation error as well as trying to print the filename

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  • C socket programming: select() is returning 0 despite messages sent from server

    - by Fantastic Fourier
    Hey all, I'm using select() to recv() messages from server, using TCP/IP. When I send() messages from the server, it returns a reasonable number of bytes, saying it's sent successful. And it does get to the client successfully when I use while loop to just recv(). Everything is fine and dandy. while(1) recv() // obviously pseudocode However, when I try to use select(), select() returns 0 from timeout (which is set to 1 second) and for the life of me I cannot figure out why it doesn't see the messages sent from the server. I should also mention that when the server disconnects, select() doesn't see that either, where as if I were to use recv(), it would return 0 to indicate that the connection using the socket has been closed. Any inputs or thoughts are deeply appreciated. #include <arpa/inet.h> #include <errno.h> #include <fcntl.h> #include <netdb.h> #include <netinet/in.h> #include <pthread.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <strings.h> #include <sys/select.h> #include <sys/socket.h> #include <sys/time.h> #include <sys/types.h> #include <time.h> #include <unistd.h> #define SERVER_PORT 10000 #define MAX_CONNECTION 20 #define MAX_MSG 50 struct client { char c_name[MAX_MSG]; char g_name[MAX_MSG]; int csock; int host; // 0 = not host of a multicast group struct sockaddr_in client_address; struct client * next_host; struct client * next_client; }; struct fd_info { char c_name[MAX_MSG]; int socks_inuse[MAX_CONNECTION]; int sock_fd, max_fd; int exit; struct client * c_sys; struct sockaddr_in c_address[MAX_CONNECTION]; struct sockaddr_in server_address; struct sockaddr_in client_address; fd_set read_set; }; struct message { char c_name[MAX_MSG]; char g_name[MAX_MSG]; char _command[3][MAX_MSG]; char _payload[MAX_MSG]; struct sockaddr_in client_address; struct client peer; }; int main(int argc, char * argv[]) { char * host; char * temp; int i, sockfd; int msg_len, rv, ready; int connection, management, socketread; int sockfds[MAX_CONNECTION]; // for three threads that handle new connections, user inputs and select() for sockets pthread_t connection_handler, manager, socket_reader; struct sockaddr_in server_address, client_address; struct hostent * hserver, cserver; struct timeval timeout; struct message msg; struct fd_info info; info.exit = 0; // exit information: if exit = 1, threads quit info.c_sys = NULL; // looking up from the host database if (argc == 3) { host = argv[1]; // server address strncpy(info.c_name, argv[2], strlen(argv[2])); // client name } else { printf("plz read the manual, kthxbai\n"); exit(1); } printf("host is %s and hp is %p\n", host, hserver); hserver = gethostbyname(host); if (hserver) { printf("host found: %s\n", hserver->h_name ); } else { printf("host not found\n"); exit(1); } // setting up address and port structure information on serverside bzero((char * ) &server_address, sizeof(server_address)); // copy zeroes into string server_address.sin_family = AF_INET; memcpy(&server_address.sin_addr, hserver->h_addr, hserver->h_length); server_address.sin_port = htons(SERVER_PORT); bzero((char * ) &client_address, sizeof(client_address)); // copy zeroes into string client_address.sin_family = AF_INET; client_address.sin_addr.s_addr = htonl(INADDR_ANY); client_address.sin_port = htons(SERVER_PORT); // opening up socket sockfd = socket(AF_INET, SOCK_STREAM, 0); if (sockfd < 0) exit(1); else { printf("socket is opened: %i \n", sockfd); info.sock_fd = sockfd; } // sets up time out option for the bound socket timeout.tv_sec = 1; // seconds timeout.tv_usec = 0; // micro seconds ( 0.5 seconds) setsockopt(sockfd, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(struct timeval)); // binding socket to a port rv = bind(sockfd, (struct sockaddr *) &client_address, sizeof(client_address)); if (rv < 0) { printf("MAIN: ERROR bind() %i: %s\n", errno, strerror(errno)); exit(1); } else printf("socket is bound\n"); printf("MAIN: %li \n", client_address.sin_addr.s_addr); // connecting rv = connect(sockfd, (struct sockaddr *) &server_address, sizeof(server_address)); info.server_address = server_address; info.client_address = client_address; info.sock_fd = sockfd; info.max_fd = sockfd; printf("rv = %i\n", rv); if (rv < 0) { printf("MAIN: ERROR connect() %i: %s\n", errno, strerror(errno)); exit(1); } else printf("connected\n"); fd_set readset; FD_ZERO(&readset); FD_ZERO(&info.read_set); FD_SET(info.sock_fd, &info.read_set); while(1) { readset = info.read_set; printf("MAIN: %i \n", readset); ready = select((info.max_fd)+1, &readset, NULL, NULL, &timeout); if(ready == -1) { sleep(2); printf("TEST: MAIN: ready = -1. %s \n", strerror(errno)); } else if (ready == 0) { sleep(2); printf("TEST: MAIN: ready = 0. %s \n", strerror(errno)); } else if (ready > 0) { printf("TEST: MAIN: ready = %i. %s at socket %i \n", ready, strerror(errno), i); for(i = 0; i < ((info.max_fd)+1); i++) { if(FD_ISSET(i, &readset)) { rv = recv(sockfd, &msg, 500, 0); if(rv < 0) continue; else if(rv > 0) printf("MAIN: TEST: %s %s \n", msg._command[0], msg._payload); else if (rv == 0) { sleep(3); printf("MAIN: TEST: SOCKET CLOSEDDDDDD \n"); } FD_CLR(i, &readset); } } } info.read_set = readset; } // close connection close(sockfd); printf("socket closed. BYE! \n"); return(0); }

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  • COM(C++) Programming Tutorials

    - by Deep-B
    Hey guys, I was wondering if there're any good sites that deal with learning C++/COM from the ground up? Looking for something like a crash course (two weeks, and not being hypothetical here). Assume knowledge in standard C/C++, or at least not a complete dummy.

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  • How to learn about iPhone jailbroken programming?

    - by tomorini
    I'm interested in learning about what additional features and APIs an app has access to when an iPhone is jailbroken. Can someone provide me with some basic resources to learn about this? I would be most interested in: documentation on the private APIs filesystem layout app configuration, e.g. how did WinterBoard replace SpringBoard? Apps that replace the lockscreen? tools needed Suggestions appreciated.

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  • Android programming: Authentication and data exchange with Java EE

    - by Konsumierer
    I am having a Java application running in a Tomcat server using Spring, Hibernate, etc. and a two web interfaces, one implemented in Tapestry 5 and the other one using Flex with BlazeDS and Spring-BlazeDS. In my first android application I would now like to log in to the server and retrieve some data. I´m wondering how I could achieve this in a secure way. First of all I need to know which technology is the best to retrieve data from the server and how can I restrict the access to users only that have been successfully authenticated. With what I read until now I would try to implement a HTTPServlet on the server and make server calls via HTTP Client. In the servlet I could probably use the HTTPSession to check if the request comes from an authenticated user. And the data I would try to send serialized (JSON). Unfortunately, I´ve never done those things and maybe I´m on the wrong way and there are more comfortable solutions.

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  • Extend legacy site with another server-side programming platform best practice

    - by Andrew Florko
    Company I work for have a site developed 6-8 years ago by a team that was enthusiastic enough to use their own private PHP-based CMS. I have to put dynamic data from one intranet company database on this site in one week: 2-3 pages. I contacted company site administrator and she showed me administrative part - CMS allows only to insert html blocks & manage site map (site is deployed on machine that is inside company & fully accessible & upgradeable). I'm not a PHP-guy & I don't want to dive into legacy hardly-who-ever-heard-about CMS engine I also don't want to contact developers team, 'cos I'm not sure they are still present and capable enough to extend this old days site and it'll take too much time anyway. I am about to deploy helper asp.net site on IIS with 2-3 pages required & refer helper site via iframe from present site. New pages will allow to download some dynamic content from present site also. Is it ok and what are the pitfalls with iframe approach?

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  • a question in NS c programming

    - by bahar
    Hi I added a new patch to my NS and I've seen thise two errors. Does anyone Know what I can do? error: specialization of 'bool std::less<_Tp::operator()(const _Tp&, const _Tp&) const [with _Tp = _AlgorithmTime]' in different namespace from definition of 'bool std::less<_Tp::operator()(const _Tp&, const _Tp&) const [with _Tp = _AlgorithmTime]' and the errors are from this code typedef struct _AlgorithmTime { // Round. int round; // Fase. int fase; // Valore massimo di fase. int last_fase; public: _AlgorithmTime() { round = 0; fase = 0; last_fase = 0; } // Costruttore. _AlgorithmTime(int r, int f, int l) { round = r; fase = f; last_fase = l; } // Costruttore. _AlgorithmTime(const _AlgorithmTime & t) { round = t.round; fase = t.fase; last_fase = t.last_fase; } // Operatore di uguaglianza. bool operator== (struct _AlgorithmTime & t) { return ((t.fase == fase) && (t.round == round)); } // Operatore minore. bool operator < (struct _AlgorithmTime & t) { if (round < t.round) return true; if (round > t.round) return false; if (fase < t.fase) return true; return false; } // Operatore maggiore. bool operator > (struct _AlgorithmTime & t) { if (round > t.round) return true; if (round < t.round) return false; if (fase > t.fase) return true; return false; } void operator++ () { if (fase == last_fase) { round++; fase = 0; return; } fase++; } void operator-- () { if (fase == 0) { round--; fase = last_fase; return; } fase--; } }AlgorithmTime; template< bool std::less::operator()(const AlgorithmTime & t1, const AlgorithmTime & t2)const { if (t1.round < t2.round) return true; if (t1.round t2.round) return false; if (t1.fase < t2.fase) return true; return false; } Thanks

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  • Best programming based games

    - by Matt Sheppard
    Back when I was at school, I remember tinkering with a Mac game where you programmed little robots in a sort of pseudo-assembler language which could then battle each other. They could move themselves around the arena, look for opponents in different directions, and fire some sort of weapon. Pretty basic stuff, but I remember it quite fondly, even if I can't remember the name. Are there any good modern day equivalents?

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  • How HID devices work when programming?

    - by user1008476
    I have a barcode scanner works as HID device. Everytime a barcode scans it goes directly to windows keyboard, for example if I open notepad I can see the barcode typed there. As far as I know programmatically is it possible to to read HID data from your HID devices. But what happens if the user is already on a form with a text edit control? The scanned code will go inside the text box. Can you block incoming text and make a background-only processing? Can you explain the theory please?

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  • iPhone programming guideline : List / detail / modify

    - by Oliver
    Hello, I have a program that displays a list (a TableView). When the user clicks an item, it's detail is shown. On the detail view, the user can ask to modify it so a modify window is shown. Here, the user can ask to delete the item. I would like at this time return to the list with the item deleted from the list and from the data source. There may be thousands of methods to do this, but I wonder which is the best / good one. Could you help me, and/or give me a good reference to read about this ? Thank you.

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  • Event driven programming in perl?

    - by TheGNUGuy
    Hey everyone, I'm trying to make a jabber bot and I am having trouble keeping it running while waiting for messages. How do I get my script to continuously run? I have tried calling a subroutine that has a while loop that I , in theory, have set up to check for any messages and react accordingly but my script isn't behaving that way. Here is my source: http://pastebin.com/03Habbvh

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  • How does Object Oriented Programming work?

    - by venom
    Hello, I am not sure about some things in OOP. If I have Class1, which has some private field, for example private Field field1, and make getField1 () { return field1; } then I have some class with constructor public Class2 (Field field) { someMethod(field); } And then I call constructor of Class2 in Class3 like: Class2 cl = new Class2(instanceOfClass1.getField1()); And now the question: Am I working with field1 of instanceOfClass1 in someMethod(field)?

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  • Programming error in Java Socket

    - by Akhil K Nambiar
    Can you tell me what is the error in this code? Socket socket = new Socket(hostname, port); PrintWriter out = new PrintWriter(socket.getOutputStream(), true); //DataInputStream is = new DataInputStream(socket.getInputStream()); out.println("hi"); System.out.print(in.readLine()); The Server Socket program is written in .Net and it echoes back the data. The data is sent successfully but could not be retrieved properly. I tried the same by using the linux command nc 192.168.1.6 8425 (enter) Hi (Sent data) Hi (recieved data) When I checked the code the data is found to have sent as byteStream in .Net. Is that a problem. In that case what modification should I make.

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  • Conditional interface programming for iPad?

    - by Fyrian
    Hi everyone! I'm working on an app for the iPad and am a little over my head with one issue. Is it possible to build an app for iPad that uses a function to control which interface layout is displayed? Something like "if these parameters are met, use XIB file "a" else use XIB file "b". I know that's not in any kind of legitimate format, but you get the idea. If this is possible, does anyone know of any tutorials on how to do it or sample code I could look at? Thanks!

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