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  • Interop Structure: Should Unsigned Short be Mapped to byte[]?

    - by Ngu Soon Hui
    I have such a C++ structure: typedef struct _FILE_OP_BLOCK { unsigned short fid; // objective file ID unsigned short offset; // operating offset unsigned char len; // buffer length(update) // read length(read) unsigned char buff[MAX_BUFF_SIZE]; } FILE_OP_BLOCK; And now I want to map it in .Net. The tricky thing is that the I should pass a 2 byte array for fid, and integer for len, even though in C# fid is an unsigned short and len is an unsigned char I wonder whether my structure ( in C#) below is correct? public struct File_OP_Block { [MarshalAs(UnmanagedType.ByValArray, SizeConst = 2)] public byte[] fid; public ushort offset; public byte length; [MarshalAs(UnmanagedType.ByValArray, SizeConst = 240)] public char[] buff; }

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  • Improving I/O performance in C++ programs[external merge sort]

    - by Ajay
    I am currently working on a project involving external merge-sort using replacement-selection and k-way merge. I have implemented the project in C++[runs on linux]. Its very simple and right now deals with only fixed sized records. For reading & writing I use (i/o)fstream classes. After executing the program for few iterations, I noticed that I/O read blocks for requests of size more than 4K(typical block size). Infact giving buffer sizes greater than 4K causes performance to decrease. The output operations does not seem to need buffering, linux seemed to take care of buffering output. So I issue a write(record) instead of maintaining special buffer of writes and then flushing them out at once using write(records[]). But the performance of the application does not seem to be great. How could I improve the performance? Should I maintain special I/O threads to take care of reading blocks or are there existing C++ classes providing this abstraction already?(Something like BufferedInputStream in java)

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  • Problems updating a textBox ASP.NET

    - by Roger Filipe
    Hello, I'm starting in asp.net and am having some problems that I do not understand. The problem is this, I am building a site for news. Every news has a title and body. I have a page where I can insert news, this page uses a textbox for each of the fields (title and body), after clicking the submit button everything goes ok and saves the values in the database. And o have another page where I can read the news, I use labels for each of the camps, these labels are defined in the Page_Load. Now I'm having problems on the page where I can edit the news. I am loading two textboxes (title and body) in the Page_Load, so far so good, but then when I change the text and I click the submit button, it ignores the changes that I made in the text and saves the text loaded in Page_Load. This code doesn't show any database connection but you can understand what i'm talking about. protected void Page_Load(object sender, EventArgs e) { textboxTitle.Text = "This is the title of the news"; textboxBody.Text = "This is the body of the news "; } I load the page, make the changes in the text , and then click submit. protected void btnSubmit_Click(object sender, EventArgs e) { String title = textboxTitle.Text; String body = textboxBody.Text; Response.Write("Title: " + title + " || "); Response.Write("Body: " + body ); } Nothing happens, the text in the textboxes is always the one I loaded in the page_load, how do I update the Text in the textboxes?

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  • Switch gettext translated language with original language

    - by Ruben
    Hi everyone, I started my PHP application with all text in German, then used gettext to extract all strings and translate them to English. So, now I have a .po file with all msgids in German and msgstrs in English. I want to switch them, so that my source code contains the English as msgids. There are numerous reasons for this: More translators will know English, so it is only appropriate to serve them up a file with msgids in English. I could always switch the file before I give it out and after I receive it It would help me to write English object & function names and comments if the content text was also English. I'd like to do that, so the project is more open to other Open Source collaborators (more likely to know English than German). I could do this manually and this is the sort of task where I anticipate it will take me more time to write an automated routine for it (because I'm very bad with shell scripts) than do it by hand. But I also anticipate despising every minute of manual computer labour (feels like a oxymoron, right?) like I always do. Has someone done this before? I figured this would be a common problem, but couldn't find anything. Many thanks ahead. Sample Problem: <title><?=_('Routinen')?></title> #: /users/ruben/sites/v/routinen.php:43 msgid "Routinen" msgstr "Routines"

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  • where did the _syscallN macros go in <linux/unistd.h>?

    - by Evan Teran
    It used to be the case that if you needed to make a system call directly in linux without the use of an existing library, you could just include <linux/unistd.h> and it would define a macro similar to this: #define _syscall3(type,name,type1,arg1,type2,arg2,type3,arg3) \ type name(type1 arg1,type2 arg2,type3 arg3) \ { \ long __res; \ __asm__ volatile ("int $0x80" \ : "=a" (__res) \ : "0" (__NR_##name),"b" ((long)(arg1)),"c" ((long)(arg2)), \ "d" ((long)(arg3))); \ if (__res>=0) \ return (type) __res; \ errno=-__res; \ return -1; \ } Then you could just put somewhere in your code: _syscall3(ssize_t, write, int, fd, const void *, buf, size_t, count); which would define a write function for you that properly performed the system call. It seems that this system has been superseded by something (i am guessing that "[vsyscall]" page that every process gets) more robust. So what is the proper way (please be specific) for a program to perform a system call directly on newer linux kernels? I realize that I should be using libc and let it do the work for me. But let's assume that I have a decent reason for wanting to know how to do this :-).

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  • how to automate the testing of a text based menu

    - by Reagan Penner
    Hi there, I have a text based menu running on a remote Linux host. I am using expect to ssh into this host and would like to figure out how to interact with the menus. Interaction involves arrowing up, down and using the enter and back arrow keys. For example, Disconnect Data Collection > Utilities > Save Changes When you enter the system Disconnect is highlighted. So simply pressing enter twice you can disconnect from the system. Second enter confirms the disconnect. The following code will ssh into my system and bring up the menu. If I remove the expect eof and try to send "\r" thinking that this would select the Disconnect menu option I get the following error: "write() failed to write anything - will sleep(1) and retry..." #!/usr/bin/expect set env(TERM) vt100 set password abc123 set ipaddr 162.116.11.100 set timeout -1 match_max -d 100000 spawn ssh root@$ipaddr exp_internal 1 expect "*password:*" send -- "$password\r" expect "Last login: *\r" expect eof I have looked at the virterm and term_expect examples but cannot figure out how to tweak them to work for me. If someone can point me in the right direction I would greatly appreciate it. What I need to know is can I interact with a text based menu system and what is the correct method for doing this, examples if any exist would be great. thanks, -reagan

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  • How to use R's ellipsis feature when writing your own function?

    - by Ryan Thompson
    The R language has a nifty feature for defining functions that can take a variable number of arguments. For example, the function data.frame takes any number of arguments, and each argument becomes the data for a column in the resulting data table. Example usage: > data.frame(letters=c("a", "b", "c"), numbers=c(1,2,3), notes=c("do", "re", "mi")) letters numbers notes 1 a 1 do 2 b 2 re 3 c 3 mi The function's signature includes an ellipsis, like this: function (..., row.names = NULL, check.rows = FALSE, check.names = TRUE, stringsAsFactors = default.stringsAsFactors()) { [FUNCTION DEFINITION HERE] } I would like to write a function that does something similar, taking multiple values and consolidating them into a single return value (as well as doing some other processing). In order to do this, I need to figure out how to "unpack" the ... from the function's arguments within the function. I don't know how to do this. The relevant line in the function definition of data.frame is object <- as.list(substitute(list(...)))[-1L], which I can't make any sense of. So how can I convert the ellipsis from the function's signature into, for example, a list? To be more specific, how can I write get_list_from_ellipsis in the code below? my_ellipsis_function(...) { input_list <- get.list.from.ellipsis(...) output_list <- lapply(X=input_list, FUN=do_something_interesting) return(output_list) } my_ellipsis_function(a=1:10,b=11:20,c=21:30)

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  • Overloading operator>> for case insensitive string

    - by TheSOFan
    Given the definition of ci_string from cpp.reference.com, how would we go about implementing operator? My attempts at it involved std::read, but it doesn't seem to work (that is, gcount() properly counts the number of characters entered, but there is no output) #include <iostream> #include <cctype> #include <string> // ci_string definition goes here std::istream& operator>>(std::istream& in, ci_string& str) { return in.read(&*str.begin(), 4); } int main() { ci_string test_str; std::cin >> test_str; std::cout << test_str; return 0; }

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  • Error: "an object reference is required for the non-static field, method or property..."

    - by user300484
    Hi! Im creating an application on C#. Its function is to evualuate if a given is prime and if the same swapped number is prime as well. When I build my solution on Visual Studio, it says that "an object reference is required for the non-static field, method or property...". Im having this problem with the "volteado" and "siprimo" methods. Can you tell me where is the problem and how i can fix it? thank you! namespace ConsoleApplication1 { class Program { static void Main(string[] args) { Console.Write("Write a number: "); long a= Convert.ToInt64(Console.ReadLine()); // a is the number given by the user long av = volteado(a); // av is "a" but swapped if (siprimo(a) == false && siprimo(av) == false) Console.WriteLine("Both original and swapped numbers are prime."); else Console.WriteLine("One of the numbers isnt prime."); Console.ReadLine(); } private bool siprimo(long a) {// evaluate if the received number is prime bool sp = true; for (long k = 2; k <= a / 2; k++) if (a % k == 0) sp = false; return sp; } private long volteado(long a) {// swap the received number long v = 0; while (a > 0) { v = 10 * v + a % 10; a /= 10; } return v; } } }

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  • VB.NET 2008, Windows 7 and saving files

    - by James Brauman
    Hello, We have to learn VB.NET for the semester, my experience lies mainly with C# - not that this should make a difference to this particular problem. I've used just about the most simple way to save a file using the .NET framework, but Windows 7 won't let me save the file anywhere (or anywhere that I have found yet). Here is the code I am using to save a text file. Dim dialog As FolderBrowserDialog = New FolderBrowserDialog() Dim saveLocation As String = dialog.SelectedPath ... Build up output string ... Try ' Try to write the file. My.Computer.FileSystem.WriteAllText(saveLocation, output, False) Catch PermissionEx As UnauthorizedAccessException ' We do not have permissions to save in this folder. MessageBox.Show("Do not have permissions to save file to the folder specified. Please try saving somewhere different.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error) Catch Ex As Exception ' Catch any exceptions that occured when trying to write the file. MessageBox.Show("Writing the file was not successful.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error) End Try The problem is that this using this code throws an UnauthorizedAccessException no matter where I try to save the file. I've tried running the .exe file as administrator, and the IDE as administrator. Is this just Windows 7 being overprotective? And if so, what can I do to solve this problem? The requirements state that I be able to save a file! Thanks.

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  • C# socket blocking behavior

    - by Gearoid Murphy
    My situation is this : I have a C# tcp socket through which I receive structured messages consisting of a 3 byte header and a variable size payload. The tcp data is routed through a network of tunnels and is occasionally susceptible to fragmentation. The solution to this is to perform a blocking read of 3 bytes for the header and a blocking read of N bytes for the variable size payload (the value of N is in the header). The problem I'm experiencing is that occasionally, the blocking receive operation returns a partial packet. That is, it reads a volume of bytes less than the number I explicitly set in the receive call. After some debugging, it appears that the number of bytes it returns is equal to the number of bytes in the Available property of the socket before the receive op. This behavior is contrary to my expectation. If the socket is blocking and I explicitly set the number of bytes to receive, shouldn't the socket block until it recv's those bytes?, any help, pointers, etc would be much appreciated.

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  • need help with Java solution /newbie

    - by Racket
    Hi, I'm new to programming in general so i'm trying to be as specific as possible in this question. There's this book that i'm doing some exercises on. I managed to do more than half of what they say, but it's just one input that I have been struggling to find out. I'll write the question and thereafter my code, "Write an application that creates and prints a random phone number of the form XXX-XXX-XXXX. Include the dashes in the output. Do not let the first three digits contain an 8 or 9 (but don't be more restrictive than that), and make sure that the second set of three digits is not greater than 742. Hint: Think through the easiest way to construct the phone number. Each diigit does not have to be determined separately." OK, the highlighted sentence is what i'm looking at. Here's my code: import java.util.Random; public class PP33 { public static void main (String[] args) { Random rand = new Random(); int num1, num2, num3; num1 = rand.nextInt(900) + 100; num2 = rand.nextInt(643) + 100; num3 = rand.nextInt(9000) + 1000; System.out.println(num1+"-"+num2+"-"+num3); } } How am I suppose to do this? I'm on chapter 3 so we have not yet discussed if statements etcetera, but Aliases, String class, Packages, Import declaration, Random Class, Math Class, Formatting output (decimal- & numberFormat), Printf, Enumeration & Wrapper classes + autoboxing. So consider answer the question based only on these assumptions, please. The code doesn't have any errors. Thank you!

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  • Bash Script using Grep to search for a pattern in a file

    - by atif089
    I am writing a bash script to search for a pattern in a file using GREP. I am clueless for why it isnt working. This is the program echo "Enter file name..."; read fname; echo "Enter the search pattern"; read pattern if [ -f $fname ]; then result=`grep -i '$pattern' $fname` echo $result; fi Or is there different approach to do this ? Thanks

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  • Is DB logging more secure than file logging for my PHP web app?

    - by iama
    I would like to log errors/informational and warning messages from within my web application to a log. I was initially thinking of logging all of these onto a text file. However, my PHP web app will need write access to the log files and the folder housing this log file may also need write access if log file rotation is desired which my web app currently does not have. The alternative is for me to log the messages to the MySQL database since my web app is already using the MySQL database for all its data storage needs. However, this got me thinking that going with the MySQL option is much better than the file option since I already have a configuration file with the database access information protected using file system permissions. If I now go with the log file option I need to tinker the file and folder access permissions and this will only make my application less secure and defeats the whole purpose of logging. Is this correct? I am using XAMPP for development and am a newbie to LAMP. Please let me know your recommendations for logging. Thanks.

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  • Unit testing a Grails custom taglib based on built-in Grails taglib

    - by dipess
    I've an app based on Grails 1.3.7. And I need to write a unit test for a custom taglib that is based on the built-in taglib, <g:select /> to be specific. I checked out the solution on this previous SO post but the solution stated is not working in my case (some properties are not being prooperly mocked up). The other solution that I found was this. Using this approach, I get most of the properties of FormTagLib mocked up except for the grailsApplication property that select requires. The actual error that I get is Cannot invoke method getArtefact() on null object. How can I properly write the unit test in such a case? Edit Here are my test class and the full stacktrace. Line #45 on the stacktrace is the call to the g.select from my custom taglib. My custom taglib is something like def clientSpecificQueues = {attrs-> def queueList = taskService.getClientSpecificQueues(session.clientName) def queueLabel = "Some String" if (queueList.size() > 0){ out << queueLabel else out << g.select(name:'queueId', from: queueList, optionKey: 'id', optionValue: 'name') }

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  • Alternatives to java on android

    - by user84584
    Hello guys, I just got myself an android phone and I'm dying to start coding on it ! However I'm not a big java fan, although I can live with that, I would like to know if there're reasonable alternatives for the android virtual machine. I've done a medium sized project using clojure, however from the reviews I read, it's very slow when running on android. How about scala ? I read that some people did experiments with it in android, is it "fast enough" ? How big is the learning curve ? Cheers, Ze Maria

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  • connecting to secure database from website host

    - by jim
    Hello all, I've got a requirement to both read and write data via a .net webservice to a sqlserver database that's on a private network. this database is currently accessed via a vpn connection by remote client software (on standard desktop machines) to get latest product prices and to upload product stock sales. I've been tasked with finding a way to centralise this access from a webservice that the clients then access, rather than them using the vpn route to connect directly to the database. My question is related to my .net service's relationship to the sqlserver database. What are the options for connecting to a private network vpn from a domain host in order to achive the functionality of allowing the webservice to both read and write data to the database. For now, I'm not too concerned about the client connectivity and security (tho i appreciate that this will have to be worked out too), I'm really just interested in discovering the options available in order to allow my .net webservice to connect to the private network in as painless and transparent a way as posible. The option of switching the database onto public hosting is not an option, so I have to work with the sdcenario as described above for now, unless there's a compelling rationale presented to do otherwise. thanks all... jim

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  • sqlite3 'database is locked' won't go away with retries

    - by Azarias
    I have a sqlite3 database that is accessed by a few threads (3-4). I am aware of the general limitations of sqlite3 with regards to concurrency as stated http://www.sqlite.org/faq.html#q6 , but I am convinced that is not the problem. All of the threads both read and write from this database. Whenever I do a write, I have the following construct: try: Cursor.execute(q, params) Connection.commit() except sqlite3.IntegrityError: Notify except sqlite3.OperationalError: print sys.exc_info() print("DATABASE LOCKED; sleeping for 3 seconds and trying again") time.sleep(3) Retry On some runs, I won't even hit this block, but when I do, it never comes out of it (keeps retrying, but I keep getting the 'database is locked' error from exc_info. If I understand the reader/writer lock usage correctly, some amount of waiting should help with the contention. What this sounds like is deadlock, but I do not use any transactions in my code, and every SELECT or INSERT is simply a one off. Some threads, however, keep the same connection when they do their operation (which includes a mix of SELECTS and INSERTS and other modifiers). I would appericiate it if you could shade a light on this, and also ways around fixing it (besides using a different database engine.)

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  • How to implement python to find value between xml tags?

    - by Harshit Sharma
    I am using google site to retrieve weather information , I want to find values between XML tags. Following code give me weather condition of a city , but I am unable to obtain other parameters such as temperature and if possible explain working of split function implied in the code: import urllib def getWeather(city): #create google weather api url url = "http://www.google.com/ig/api?weather=" + urllib.quote(city) try: # open google weather api url f = urllib.urlopen(url) except: # if there was an error opening the url, return return "Error opening url" # read contents to a string s = f.read() # extract weather condition data from xml string weather = s.split("<current_conditions><condition data=\"")[-1].split("\"")[0] # if there was an error getting the condition, the city is invalid if weather == "<?xml version=": return "Invalid city" #return the weather condition return weather def main(): while True: city = raw_input("Give me a city: ") weather = getWeather(city) print(weather) if __name__ == "__main__": main() Thank You

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  • How do I create a Status Icon / System Tray Icon with custom text and transparent background using P

    - by Raugturi
    Here is the code that I have so far to define the icon: icon_bg = gtk.gdk.pixbuf_new_from_file('gmail.png') w, h = icon_bg.get_width(), icon_bg.get_height() cmap = gtk.gdk.Colormap(gtk.gdk.visual_get_system(), False) drawable = gtk.gdk.Pixmap(None, w, h, 24) drawable.set_colormap = cmap gc = drawable.new_gc() drawable.draw_pixbuf(gc, icon_bg, 0, 0, 0, 0, w, h) drawn_icon = gtk.gdk.Pixbuf(gtk.gdk.COLORSPACE_RGB, False, 8, w, h) drawn_icon.get_from_drawable(drawable, cmap, 0, 0, 0, 0, w, h) icon = gtk.status_icon_new_from_pixbuf(drawn_icon) This works to get the png into the icon, but falls short in two areas. First, transparency is not working. If I use a 22x22 png with transparent background and the image centered, I end up with sections of other active icons showing up inside of mine, like this: http://i237.photobucket.com/albums/ff311/Raugturi/22x22_image_with_transparency.png The icon it choose to steal from is somewhat random. Sometimes it's part of the dropbox icon, others the NetworkManager Applet. If I instead use this code: icon_bg = gtk.gdk.pixbuf_new_from_file('gmail.png') w, h = icon_bg.get_width(), icon_bg.get_height() cmap = gtk.gdk.Colormap(gtk.gdk.visual_get_system(), False) drawable = gtk.gdk.Pixmap(None, w, h, 24) drawable.set_colormap = cmap gc = drawable.new_gc() drawable.draw_pixbuf(gc, icon_bg, 0, 0, 0, 0, w, h) drawn_icon = gtk.gdk.Pixbuf(gtk.gdk.COLORSPACE_RGB, False, 8, 22, 22) drawn_icon.get_from_drawable(drawable, cmap, 0, 0, 3, 6, w, h) icon = gtk.status_icon_new_from_pixbuf(drawn_icon) And an image that is only 16x11 with the transparent edges removed, what I end up with is this: Same URL but file is 16x11_image_positioned_in_middle.png So how do I end up with a transparent block like the 1st one that doesn't pull in stuff from other icons? As for the second problem, I need the ability to write on the image before converting it to the icon. I tried using draw_glyphs and it told me I should be using Pango layout/context instead. Unfortunately all the Pango tutorials I could find deal with actual windows, not the status icon. Is there a good tutorial out there for Pango that would apply to this issue (and also maybe have at least some explanation of how to tell it what font to use as all of them that I found seem to lack this and it won't write anything without it). Note: Sorry for the lack of actual images and only one working link, apparently this is a spam prevention feature due to my lack of reputation.

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  • BasicDBObject or QueryBuilder and some newbie questions of Java and mongo

    - by Kevin Xu
    hi I'm a fresh newbie to mongodb Q1 using query=new BasicDBObject(); query.put("i", new BasicDBObject("$gt",13)); and query=new QueryBuilder().put("i").Greaterthan(13).get() is there any difference inside of the system? Q2 I've created a class class findkv extends BasicDBObject{ //is gt gte lt lte public findkv(String fieldname,String op,Object tvalue) { if (op=="") this.put(fieldname,tvalue); else this.put(fieldname, new BasicDBObject(op,tvalue)); } } shall I use it or shall I just use original function? Q3 I've used mongo shell for a few weeks, and was customed to it, and find writing in mongo shell faster and shorter, which side has more advantage, writing in mongo or in java? I shall dump them from mongo to mysql Q4 I've an if (statement==true) return else dowhat; seems can't be compiled I know I can write if (statement!=true) dowhat else return, but can I still write in first style? q5 my eclipse is Eclipse Java EE IDE for Web Developers. Version: Juno Release Build id: 20120614-1722 I'd like to install Perl which I haven't learned yet I choose Install Update http://e-p-i-c.sf.net/updates/testing but it doesn't work, any method to install perl to eclipse manually?

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  • What is the standard way to parse floats at runtime in C?

    - by Joel J. Adamson
    Hello, I have a scientific application for which I want to input initial values at runtime. I have an option to get them from the command line, or to get them from an input file. Either of these options are input to a generic parser that uses strtod to return a linked list of initial values for each simulation run. I either use the command-line argument or getline() to read the values. The question is, should I be rolling my own parser, or should I be using a parser-generator or some library? What is the standard method? This is the only data I will read at runtime, and everything else is set at compile time (except for output files and a few other totally simple things). Thanks, Joel

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