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  • C# problem with two threads and hardware access

    - by mack369
    I'm creating an application which communicates with the device via FT2232H USB/RS232 converter. For communication I'm using FTD2XX_NET.dll library from FTDI website. I'm using two threads: first thread continuously reads data from the device the second thread is the main thread of the Windows Form Application I've got a problem when I'm trying to write any data to the device while the receiver's thread is running. The main thread simply hangs up on ftdiDevice.Write function. I tried to synchronize both threads so that only one thread can use Read/Write function at the same time, but it didn't help. Below code responsible for the communication. Note that following functions are methods of FtdiPort class. Receiver's thread private void receiverLoop() { if (this.DataReceivedHandler == null) { throw new BackendException("dataReceived delegate is not set"); } FTDI.FT_STATUS ftStatus = FTDI.FT_STATUS.FT_OK; byte[] readBytes = new byte[this.ReadBufferSize]; while (true) { lock (FtdiPort.threadLocker) { UInt32 numBytesRead = 0; ftStatus = ftdiDevice.Read(readBytes, this.ReadBufferSize, ref numBytesRead); if (ftStatus == FTDI.FT_STATUS.FT_OK) { this.DataReceivedHandler(readBytes, numBytesRead); } else { Trace.WriteLine(String.Format("Couldn't read data from ftdi: status {0}", ftStatus)); Thread.Sleep(10); } } Thread.Sleep(this.RXThreadDelay); } } Write function called from main thread public void Write(byte[] data, int length) { if (this.IsOpened) { uint i = 0; lock (FtdiPort.threadLocker) { this.ftdiDevice.Write(data, length, ref i); } Thread.Sleep(1); if (i != (int)length) { throw new BackendException("Couldnt send all data"); } } else { throw new BackendException("Port is closed"); } } Object used to synchronize two threads static Object threadLocker = new Object(); Method that starts the receiver's thread private void startReceiver() { if (this.DataReceivedHandler == null) { return; } if (this.IsOpened == false) { throw new BackendException("Trying to start listening for raw data while disconnected"); } this.receiverThread = new Thread(this.receiverLoop); //this.receiverThread.Name = "protocolListener"; this.receiverThread.IsBackground = true; this.receiverThread.Start(); } The ftdiDevice.Write function doesn't hang up if I comment following line: ftStatus = ftdiDevice.Read(readBytes, this.ReadBufferSize, ref numBytesRead);

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  • prevent autodropdown by jquery datepicker

    - by snarebold
    hi when I append jquery datepicker to my asp textbox, by clicking on it, my browser auto shows the history of the dates i typed in a dropdownlist. Can I prevent this? Set textbox to readonly isn't a good idea because asp.net doesn't read the values from read only fields in code behind. any other ideas? thank you and best regards. marc

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  • Reading a file with a supplied name in C++

    - by Cosmina
    I must read a file with a given name (it's caled "hamlet.txt"). The class used to read the file is defined like this #ifndef READWORDS_H #define READWORDS_H /** * ReadWords class. Provides mechanisms to read a text file, and return * capitalized words from that file. */ using namespace std; #include <string> #include <fstream> class ReadWords { public: /** * Constructor. Opens the file with the default name "text.txt". * Program exits with an error message if the file does not exist. */ ReadWords(); /** * Constructor. Opens the file with the given filename. * Program exits with an error message if the file does not exist. * @param filename - a C string naming the file to read. */ ReadWords(char *filename); My definition of the members of the classis this: #include<string> #include<fstream> #include<iostream> #include "ReadWords.h" using namespace std; ReadWords::ReadWords() { wordfile.open("text.txt"); if( !wordfile ) { cout<<"Errors while opening the file!"<<endl; } } ReadWords::ReadWords(char *filename) { wordfile.open(filename); if ( !wordfile ) { cout<<"Errors while opening the file!"<<endl; } wordfile>>nextword; } And the main to test it. using namespace std; #include #include #include "ReadWords.h" int main() { char name[30]; cout<<"Please input a name for the file that you wish to open"; cin>>name; ReadWords x( name[] ); } When I complie it gives me the error: main.cpp:14: error: expected primary-expression before ']' token I know it's got something to do with the function ReadWords( char *filename), but I do not know what. Any help please?

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  • CakePHP: Can I ignore a field when reading the Model from the DB?

    - by Daniel Magliola
    In one of my models, I have a "LONGTEXT" field that has a big dump of a bunch of stuff that I never care to read, and it slows things down, since I'm moving much more data between the DB and the web app. Is there a way to specify in the model that I want CakePHP to simply ignore that field, and never read it or do anything with it? I really want to avoid the hassle of creating a separate table and a separate model, only for this field. Thanks! Daniel

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  • MOSS 2007 - list permission

    - by nav
    Hi All, I have configured my list so that users can only read and edit items they have created. I now need to configure this list so that a particular group of users can edit and read all items on this list. I know users with the 'Manage Lists' permission would be able to do this. My question is can this be configured to be even more granular to apply a permission that works like the 'Manage Lists' permission but only for a particular list, rather than all lists? Many Thanks, Nav

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  • Can I make ruby send network traffic over a specific iface?

    - by rjorgenson
    I am writing a script that grabs the external IP address along with some other information about each iface. I can't figure out how to make ruby send traffic over a specific iface(eth0 and wlan0 for example). I am currently using the open-uri library to open http://whatismyip.org and read it into a variable. def get_external_ip begin open("http://whatismyip.org") { |f| return f.read } rescue return "none" end end Is there any way to specify this at runtime of the script or from within the script itself(ideally)?

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  • Cannot run public class in one .java from another

    - by DIOS
    I have created a basic program that takes whatever is input into two textfields and exports them to a file. I would now like to encrypt that file, and alredy have the encryptor. The problem is that I cannot call it. Here is my code for the encryptor: import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.*; import javax.crypto.Cipher; import javax.crypto.CipherInputStream; import javax.crypto.CipherOutputStream; import javax.crypto.spec.SecretKeySpec; public class FileEncryptor { private String algo; private File file; public FileEncryptor(String algo,String path) { this.algo=algo; //setting algo this.file=new File(path); //settong file } public void encrypt() throws Exception{ //opening streams FileInputStream fis =new FileInputStream(file); file=new File(file.getAbsolutePath()); FileOutputStream fos =new FileOutputStream(file); //generating key byte k[] = "HignDlPs".getBytes(); SecretKeySpec key = new SecretKeySpec(k,algo.split("/")[0]); //creating and initialising cipher and cipher streams Cipher encrypt = Cipher.getInstance(algo); encrypt.init(Cipher.ENCRYPT_MODE, key); CipherOutputStream cout=new CipherOutputStream(fos, encrypt); byte[] buf = new byte[1024]; int read; while((read=fis.read(buf))!=-1) //reading data cout.write(buf,0,read); //writing encrypted data //closing streams fis.close(); cout.flush(); cout.close(); } public static void main (String[] args)throws Exception { new FileEncryptor("DES/ECB/PKCS5Padding","C:\\Users\\*******\\Desktop\\newtext").encrypt();//encrypts the current file. } } Here is the section of my file creator that is failing to call this: FileWriter fWriter = null; BufferedWriter writer = null; try{ fWriter = new FileWriter("C:\\Users\\*******\\Desktop\\newtext"); writer = new BufferedWriter(fWriter); writer.write(Data); writer.close(); f.dispose(); FileEncryptor encr = new FileEncryptor(); //problem lies here. encr.encrypt //public void that does the encryption. new complete(); //different .java that is working fine.

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  • How can I fix my program from crashing in C++?

    - by Rachel
    I'm very new to programming and I am trying to write a program that adds and subtracts polynomials. My program sometimes works, but most of the time, it randomly crashes and I have no idea why. It's very buggy and has other problems I'm trying to fix, but I am unable to really get any further coding done since it crashes. I'm completely new here but any help would be greatly appreciated. Here's the code: #include <iostream> #include <cstdlib> using namespace std; int getChoice(void); class Polynomial10 { private: double* coef; int degreePoly; public: Polynomial10(int max); //Constructor for a new Polynomial10 int getDegree(){return degreePoly;}; void print(); //Print the polynomial in standard form void read(); //Read a polynomial from the user void add(const Polynomial10& pol); //Add a polynomial void multc(double factor); //Multiply the poly by scalar void subtract(const Polynomial10& pol); //Subtract polynom }; void Polynomial10::read() { cout << "Enter degree of a polynom between 1 and 10 : "; cin >> degreePoly; cout << "Enter space separated coefficients starting from highest degree" << endl; for (int i = 0; i <= degreePoly; i++) { cin >> coef[i]; } } void Polynomial10::print() { for(int i=0;i<=degreePoly;i++) { if(coef[i] == 0) { cout << ""; } else if(i>=0) { if(coef[i] > 0 && i!=0) { cout<<"+"; } if((coef[i] != 1 && coef[i] != -1) || i == degreePoly) { cout << coef[i]; } if((coef[i] != 1 && coef[i] != -1) && i!=degreePoly ) { cout << "*"; } if (i != degreePoly && coef[i] == -1) { cout << "-"; } if(i != degreePoly) { cout << "x"; } if ((degreePoly - i) != 1 && i != degreePoly) { cout << "^"; cout << degreePoly-i; } } } } void Polynomial10::add(const Polynomial10& pol) { for(int i = 0; i<degreePoly; i++) { int degree = degreePoly; coef[degreePoly-i] += pol.coef[degreePoly-(i+1)]; } } void Polynomial10::subtract(const Polynomial10& pol) { for(int i = 0; i<degreePoly; i++) { coef[degreePoly-i] -= pol.coef[degreePoly-(i+1)]; } } void Polynomial10::multc(double factor) { //int degreePoly=0; //double coef[degreePoly]; cout << "Enter the scalar multiplier : "; cin >> factor; for(int i = 0; i<degreePoly; i++) { coef[i] *= factor; } }; Polynomial10::Polynomial10(int max) { degreePoly=max; coef = new double[degreePoly]; for(int i; i<degreePoly; i++) { coef[i] = 0; } } int main() { int choice; Polynomial10 p1(1),p2(1); cout << endl << "CGS 2421: The Polynomial10 Class" << endl << endl << endl; cout << "0. Quit\n" << "1. Enter polynomial\n" << "2. Print polynomial\n" << "3. Add another polynomial\n" << "4. Subtract another polynomial\n" << "5. Multiply by scalar\n\n"; int choiceFirst = getChoice(); if (choiceFirst != 1) { cout << "Enter a Polynomial first!"; } if (choiceFirst == 1) {choiceFirst = choice;} while(choice != 0) { switch(choice) { case 0: return 0; case 1: p1.read(); break; case 2: p1.print(); break; case 3: p2.read(); p1.add(p2); cout << "Updated Polynomial: "; p1.print(); break; case 4: p2.read(); p1.subtract(p2); cout << "Updated Polynomial: "; p1.print(); break; case 5: p1.multc(10); cout << "Updated Polynomial: "; p1.print(); break; } choice = getChoice(); } return 0; } int getChoice(void) { int c; cout << "\nEnter your choice : "; cin >> c; return c; }

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  • How do you determine an acceptable response time for DB requests?

    - by qiq
    According to this discussion of Google App Engine on Hacker News, A DB (read) request takes over 100ms on the datastore. That's insane and unusable for about 90% of applications. How do you determine what is an acceptable response time for a DB read request? I have been using App Engine without noticing any issues with DB responsiveness. But, on the other hand, I'm not sure I would even know what to look for in that regard :)

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  • C sockets, chat server and client, problem echoing back.

    - by wretrOvian
    Hi This is my chat server : #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <sys/types.h> #include <sys/socket.h> #include <netdb.h> #include <string.h> #define LISTEN_Q 20 #define MSG_SIZE 1024 struct userlist { int sockfd; struct sockaddr addr; struct userlist *next; }; int main(int argc, char *argv[]) { // declare. int listFD, newFD, fdmax, i, j, bytesrecvd; char msg[MSG_SIZE], ipv4[INET_ADDRSTRLEN]; struct addrinfo hints, *srvrAI; struct sockaddr_storage newAddr; struct userlist *users, *uptr, *utemp; socklen_t newAddrLen; fd_set master_set, read_set; // clear sets FD_ZERO(&master_set); FD_ZERO(&read_set); // create a user list users = (struct userlist *)malloc(sizeof(struct userlist)); users->sockfd = -1; //users->addr = NULL; users->next = NULL; // clear hints memset(&hints, 0, sizeof hints); // prep hints hints.ai_family = AF_INET; hints.ai_socktype = SOCK_STREAM; hints.ai_flags = AI_PASSIVE; // get srver info if(getaddrinfo("localhost", argv[1], &hints, &srvrAI) != 0) { perror("* ERROR | getaddrinfo()\n"); exit(1); } // get a socket if((listFD = socket(srvrAI->ai_family, srvrAI->ai_socktype, srvrAI->ai_protocol)) == -1) { perror("* ERROR | socket()\n"); exit(1); } // bind socket bind(listFD, srvrAI->ai_addr, srvrAI->ai_addrlen); // listen on socket if(listen(listFD, LISTEN_Q) == -1) { perror("* ERROR | listen()\n"); exit(1); } // add listfd to master_set FD_SET(listFD, &master_set); // initialize fdmax fdmax = listFD; while(1) { // equate read_set = master_set; // run select if(select(fdmax+1, &read_set, NULL, NULL, NULL) == -1) { perror("* ERROR | select()\n"); exit(1); } // query all sockets for(i = 0; i <= fdmax; i++) { if(FD_ISSET(i, &read_set)) { // found active sockfd if(i == listFD) { // new connection // accept newAddrLen = sizeof newAddr; if((newFD = accept(listFD, (struct sockaddr *)&newAddr, &newAddrLen)) == -1) { perror("* ERROR | select()\n"); exit(1); } // resolve ip if(inet_ntop(AF_INET, &(((struct sockaddr_in *)&newAddr)->sin_addr), ipv4, INET_ADDRSTRLEN) == -1) { perror("* ERROR | inet_ntop()"); exit(1); } fprintf(stdout, "* Client Connected | %s\n", ipv4); // add to master list FD_SET(newFD, &master_set); // create new userlist component utemp = (struct userlist*)malloc(sizeof(struct userlist)); utemp->next = NULL; utemp->sockfd = newFD; utemp->addr = *((struct sockaddr *)&newAddr); // iterate to last node for(uptr = users; uptr->next != NULL; uptr = uptr->next) { } // add uptr->next = utemp; // update fdmax if(newFD > fdmax) fdmax = newFD; } else { // existing sockfd transmitting data // read if((bytesrecvd = recv(i, msg, MSG_SIZE, 0)) == -1) { perror("* ERROR | recv()\n"); exit(1); } msg[bytesrecvd] = '\0'; // find out who sent? for(uptr = users; uptr->next != NULL; uptr = uptr->next) { if(i == uptr->sockfd) break; } // resolve ip if(inet_ntop(AF_INET, &(((struct sockaddr_in *)&(uptr->addr))->sin_addr), ipv4, INET_ADDRSTRLEN) == -1) { perror("* ERROR | inet_ntop()"); exit(1); } // print fprintf(stdout, "%s\n", msg); // send to all for(j = 0; j <= fdmax; j++) { if(FD_ISSET(j, &master_set)) { if(send(j, msg, strlen(msg), 0) == -1) perror("* ERROR | send()"); } } } // handle read from client } // end select result handle } // end looping fds } // end while return 0; } This is my client: #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <sys/types.h> #include <sys/socket.h> #include <netdb.h> #include <string.h> #define MSG_SIZE 1024 int main(int argc, char *argv[]) { // declare. int newFD, bytesrecvd, fdmax; char msg[MSG_SIZE]; fd_set master_set, read_set; struct addrinfo hints, *srvrAI; // clear sets FD_ZERO(&master_set); FD_ZERO(&read_set); // clear hints memset(&hints, 0, sizeof hints); // prep hints hints.ai_family = AF_INET; hints.ai_socktype = SOCK_STREAM; hints.ai_flags = AI_PASSIVE; // get srver info if(getaddrinfo(argv[1], argv[2], &hints, &srvrAI) != 0) { perror("* ERROR | getaddrinfo()\n"); exit(1); } // get a socket if((newFD = socket(srvrAI->ai_family, srvrAI->ai_socktype, srvrAI->ai_protocol)) == -1) { perror("* ERROR | socket()\n"); exit(1); } // connect to server if(connect(newFD, srvrAI->ai_addr, srvrAI->ai_addrlen) == -1) { perror("* ERROR | connect()\n"); exit(1); } // add to master, and add keyboard FD_SET(newFD, &master_set); FD_SET(STDIN_FILENO, &master_set); // initialize fdmax if(newFD > STDIN_FILENO) fdmax = newFD; else fdmax = STDIN_FILENO; while(1) { // equate read_set = master_set; if(select(fdmax+1, &read_set, NULL, NULL, NULL) == -1) { perror("* ERROR | select()"); exit(1); } // check server if(FD_ISSET(newFD, &read_set)) { // read data if((bytesrecvd = recv(newFD, msg, MSG_SIZE, 0)) < 0 ) { perror("* ERROR | recv()"); exit(1); } msg[bytesrecvd] = '\0'; // print fprintf(stdout, "%s\n", msg); } // check keyboard if(FD_ISSET(STDIN_FILENO, &read_set)) { // read data from stdin if((bytesrecvd = read(STDIN_FILENO, msg, MSG_SIZE)) < 0) { perror("* ERROR | read()"); exit(1); } msg[bytesrecvd] = '\0'; // send if((send(newFD, msg, bytesrecvd, 0)) == -1) { perror("* ERROR | send()"); exit(1); } } } return 0; } The problem is with the part where the server recv()s data from an FD, then tries echoing back to all [send() ]; it just dies, w/o errors, and my client is left looping :(

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  • Reading XML by Dataset

    - by Sathish
    I using a dataset to read an xml file as shown below DataSet ds = new DataSet(); ds.ReadXml("C:\test.xml"); test.xml contains OMID Yes AssumptOMID int 10 ClientName Yes AssumptClient string 50 OppName Yes AssumptProjectName string 50 now i want to read fieldInfo in one dataset/datatable and settings in another dataset/datatable Please help me with the code

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  • Making Custom DataGridViewCell ReadOnly

    - by Ashton Halladay
    I am making several custom DataGridViewCell classes to handle various cases in my C# application. One of the custom classes is associated with read-only data, so I'm attempting to make the cell itself read-only. I initially tried setting the ReadOnly property in the constructor, but doing so causes an InvalidOperationException: "ReadOnly property of a cell cannot be set before it is added to a row." Which method should I override (i.e., which method adds the cell to the row), so that I can set the ReadOnly property?

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  • Reading numeric Date value from CSV file to data.frame in "R"

    - by Dick Eshelman
    D <- read.csv("sample1.csv", header = FALSE, sep = ",") D V1 V2 V3 V4 1 20100316 109825 352120 239065 2 20100317 108625 352020 239000 3 20100318 109125 352324 241065 D[,1] [1] 20100316 20100317 20100318 In the above example how do I get the data in D[,1] to be read, and stored as date values: 2010-03-16, 2010-03-17, 2010-03-18 ? I have lots of data files in this format. TIA,

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  • Several ifstream vs. ifstream + constant seeking

    - by SpyBot
    I'm writing an external merge sort. It works like that: read k chunks from big file, sort them in memory, perform k-way merge, done. So I need to sequentially read from different portions of the file during the k-way merge phase. What's the best way to do that: several ifstreams or one ifstream and seeking? Also, is there a library for easy async IO?

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  • mysql db image convert to file

    - by ntan
    Hi i am writing a converter from Oracle to mysql In Oracle the images are stored in db. I want to read the content of the image and save to file system I suppose that i have to read the blob entry and using php file commands create the file (am i right) What about image type. Should i save as jpg (what if the store image is not jpg) Any suggestion are welcome

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  • Reading MP3 files

    - by Midas
    I want to read MP3 files in C++ and I prefer to write my own code for this. Basically to learn how the filetype works. I want to read all the bits of hex data of a MP3 file and have my speakers play it. :) I have no idea where to start since I don't yet know how data is actually stored into a MP3 file. Thanks for your help

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  • xml file reading

    - by Dilse Naaz
    How to read an xml file in silverlight using webclient. I have one task, in this the xml file that i stored in my machine will read and the content od the xml file will display on a data grid. how it will be done?

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  • javascript conflict on accesing DOM

    - by justjoe
    i read this statement from a book i read The Document Object Model or DOM is really not a part of JavaScript but a separate entity existing outside it. Although you can use JavaScript to manipulate DOM objects, other scripting languages may equally well access them too. what is the best way to avoid conflict between javascript and other client-siede scripting language when we have to deal with XMLHTTPRequest object

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  • c++ how to write code for atoi and find in a function called getTriplet()

    - by Gerri
    Hello I am trying to write code for a function called Triplet getTriplet() and I must use find and atoi in this fuction to call the array[3] = {0, 1, 2} and find the "," and find the "()" in the program? I am so lost. I have read and read and cannot locate any informatin which really touches on the subjects enough to give me an understanding of what I am suppose to do. Please help if you can! Thanks in advance.

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  • Extract text from PDF (google app engine)

    - by Miroslav Bajtoš
    Is there any free Java library for extracting text from PDF, that is compatible with Google Application Engine? I've read about PDFJet, but it can't read PDF, can it? Is there perhaps other way how to extract text from PDF? I tried http://www.pdfdownload.org/, unfortunately they don't handle non-English characters correctly.

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  • T-SQL GO Statement

    - by coffeeaddict
    I have read and read over MSDN, etc. Ok, so it signals the end of a batch. What defines a batch? I don't see why I need go when I'm pasting in a bunch of scripts to be run all at the same time. I've never understood GO. Can anyone explain this better and when I need to use it (after how many or what type of transactions)?

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  • Trouble with encoding and urllib

    - by Ockonal
    Hello, I'm loading web-page using urllib. Ther eis russian symbols, but page encoding is 'utf-8' 1 pageData = unicode(requestHandler.read()).decode('utf-8') UnicodeDecodeError: 'ascii' codec can't decode byte 0xd0 in position 262: ordinal not in range(128) 2 pageData = requestHandler.read() soupHandler = BeautifulSoup(pageData) print soupHandler.findAll(...) UnicodeEncodeError: 'ascii' codec can't encode characters in position 340-345: ordinal not in range(128)

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