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  • apt - Remove not configured package

    - by madflow
    I have a Linux-Mint Debian Edition System. When I install sendmail I get an infinite loop. Reading configuration from /etc/mail/sendmail.conf. Validating configuration. Creating /etc/mail/databases... Reading configuration from /etc/mail/sendmail.conf. Validating configuration. Creating /etc/mail/databases... When I try dpkg --configure -a it is the same. Now I want to simple remove sendmail from the installation queue - but I can't simply do that, because apt-get always wants to configure sendmail first. Is there a way to force apt-get to remove sendmail or set it to "configured" - even though the package is not properly configured?

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  • Mysqld not starting due to apparent db corruption

    - by pitosalas
    I am very new at admining mysql, and bad for me, something caused the db to get clobbered. There are many error messages in the log that I am not sure how to safely proceed. Can you give some tips? Here's the log: 110107 15:07:15 mysqld started 110107 15:07:15 InnoDB: Database was not shut down normally! InnoDB: Starting crash recovery. InnoDB: Reading tablespace information from the .ibd files... InnoDB: Restoring possible half-written data pages from the doublewrite InnoDB: buffer... 110107 15:07:15 InnoDB: Starting log scan based on checkpoint at InnoDB: log sequence number 35 515914826. InnoDB: Doing recovery: scanned up to log sequence number 35 515915839 InnoDB: 1 transaction(s) which must be rolled back or cleaned up InnoDB: in total 1 row operations to undo InnoDB: Trx id counter is 0 1697553664 110107 15:07:15 InnoDB: Starting an apply batch of log records to the database... InnoDB: Progress in percents: 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 InnoDB: Apply batch completed InnoDB: Starting rollback of uncommitted transactions InnoDB: Rolling back trx with id 0 1697553198, 1 rows to undoInnoDB: Error: trying to access page number 3522914176 in space 0, InnoDB: space name ./ibdata1, InnoDB: which is outside the tablespace bounds. InnoDB: Byte offset 0, len 16384, i/o type 10 110107 15:07:15InnoDB: Assertion failure in thread 3086403264 in file fil0fil.c line 3922 InnoDB: We intentionally generate a memory trap. InnoDB: Submit a detailed bug report to http://bugs.mysql.com. InnoDB: If you get repeated assertion failures or crashes, even InnoDB: immediately after the mysqld startup, there may be InnoDB: corruption in the InnoDB tablespace. Please refer to InnoDB: http://dev.mysql.com/doc/mysql/en/Forcing_recovery.html InnoDB: about forcing recovery. mysqld got signal 11; This could be because you hit a bug. It is also possible that this binary or one of the libraries it was linked against is corrupt, improperly built, or misconfigured. This error can also be caused by malfunctioning hardware. We will try our best to scrape up some info that will hopefully help diagnose the problem, but since we have already crashed, something is definitely wrong and this may fail. key_buffer_size=0 read_buffer_size=131072 max_used_connections=0 max_connections=100 threads_connected=0 It is possible that mysqld could use up to key_buffer_size + (read_buffer_size + sort_buffer_size)*max_connections = 217599 K bytes of memory Hope that's ok; if not, decrease some variables in the equation. thd=(nil) Attempting backtrace. You can use the following information to find out where mysqld died. If you see no messages after this, something went terribly wrong... Cannot determine thread, fp=0xbffc55ac, backtrace may not be correct. Stack range sanity check OK, backtrace follows: 0x8139eec 0x83721d5 0x833d897 0x833db71 0x832aa38 0x835f025 0x835f7a3 0x830a77e 0x8326b57 0x831c825 0x8317b8d 0x82a9e66 0x8315732 0x834fc9a 0x828d7c3 0x81c29dd 0x81b5620 0x813d9fe 0x40fdf3 0x80d5ff1 New value of fp=(nil) failed sanity check, terminating stack trace! Please read http://dev.mysql.com/doc/mysql/en/Using_stack_trace.html and follow instructions on how to resolve the stack trace. Resolved stack trace is much more helpful in diagnosing the problem, so please do resolve it The manual page at http://www.mysql.com/doc/en/Crashing.html contains information that should help you find out what is causing the crash. 110107 15:07:15 mysqld ended

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  • Adding a MySQL StoredProcedure causes not responding state

    - by Omie
    I'm on Windows 7 ultimate 32bit + xampp 1.7.2 [MySQL v5.1.37] This is my stored procedure : delimiter // CREATE PROCEDURE updatePoints(IN parentid INT(5),IN userid INT(5)) DECLARE chpoints INT(5); BEGIN SELECT points INTO chpoints FROM quiz_challenges WHERE id = parentid; UPDATE quiz_users SET points = points + chpoints WHERE forumid=userid; END; // delimiter ; At first it was showing error 1064 while creating stored procedure. I added delimiters part and when I tried running the query from phpmyadmin, Firefox went into not responding state. After that I started Internet Explorer and tried opening my pages which use the same database, it worked fine. However, I tried opening phpmyadmin and IE went into not responding state as well. I restarted both servers. Later restarted PC. Tried again but its same behavior. So whats wrong with this tiny little code ? Am I missing something which might be causing infinite loop ? Thanks

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  • dhcp code for pxe server

    - by avoq
    I'm trying to understand every single line of the following script but to no avail. I'd be glad if someone could help me. For sure I know its purpose is to start the DHCP server as well as the TFTP...But I'm stuck: killall dnsmasq 2>/dev/null dnsmasq --enable-tftp --tftp-root=$PXEDATA/boot --dhcp-boot=pxelinux.0,"$IP",$IP --dhcp-range=$(echo $IP | cut -d. -f1-3).50,$(echo $IP | cut -d. -f1-3).250, infinite --dhcp-option=option:router,192.168.0.254 --log-dhcp Why killall, why dnsmasq 2 What does "2" stand for? "--" what does it mean? Thanks a lot.

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  • Managing PHP processes on Windows 7 (with WAMP)

    - by Andrea
    Is there a way to manage (especially list and kill) long-running PHP processes on a Windows 7 system set up with WAMP? Every once in a while, I'll accidentally throw an infinite loop into a PHP process and want to kill it. Right now, all I can think to do is to restart all my WAMP services but sometimes the PHP processes manage to survive right through the restart, i.e., I still see them outputting to logs even after WAMP's restarted. And if the process isn't logging, then I have no way at all to know when/if it's been killed. Not to mention, this will wipe out everything I'm doing with WAMP, not just a single process. I don't seem to see anything relevant in the Windows Task Manager, but maybe I'm missing something.

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  • How to rewrite index.php (and other valid default files) to the document root using mod_rewrite?

    - by TMG
    Hello, I would like to redirect index.php, as well as any other valid default file (e.g. index.html, index.asp, etc.) to the document root (which contains index.php) with something like this: RewriteRule ^index\.(php|htm|html|asp|cfm|shtml|shtm)/?$ / [NC,L] However, this is of course giving me an infinite redirect loop. What's the right way to do this? If possible, I'd like to have this work in both the development and production environment, so I don't want to specify an explicit url like http://www.mysite.com/ as the target. Thanks!

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  • Windows XP crashes by GT610 driver (nv4_disp)

    - by undone
    I have a PC which was working fine but one day screen went dark and nothing was shown. I thought the problem is graphic card, so I replaced it with new one. I bought a new graphic card (GeForce 610) and installed it on my system. I formatted my hard-drive and installed a fresh Windows XpSp3 and its drivers. Everything was fine but after installing graphic card's driver, I got an error saying windows got stuck in an infinite loop and it couldn't get out (in nv4_disp). I uninstalled it and downloaded its last version and installed it. Unfortunately, I got the same error and windows restated! Here's my system: Pascal Motherboard PT880PRO Intel CPU Windows XPSp3 I searched this issue on the internet and I found bunch of suggestions (from cleaning hardware to installing latest version of its driver) but nothing help! Any help would be appreciated! Thanks.

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  • Simple Chat with php

    - by MatrixOnTheLine
    in chat.php $data = getCache($room); while(1){ if($data == false || empty($data[1]) ) sleep(10); else break; } in sendmemcache.php $value = $_GET['value']; setCache($room,array($username,$value)); However, in infinite loop $data's value never change. I send $value with manuel for sendmemcache.ophp. sendmemcache.php never finish its proces. (Always "Transferring data ....") How can i resolve this ?

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  • online to do list manager with subtasks

    - by alex
    I'm looking for an online task list tool, what I absolutely need is the infinite number of subtask levels, because that's how my mind works. I don't need collaboration. There are a lot of great to do list sites out there, but for some reason most of them have only one subtask level or no subtasks at all. I know about todoist, but its interface doesn't work for me. There must be many more, I guess. Links to desktop tools with the feature are also appreciated as long as they are cross-platform.

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  • Imagemagick/File upload abuse causing my memory errors

    - by kidcapital
    I had been running out of memory on my server lately and I noticed some individuals uploading the same "file" over and over in quick succession which locks up my instance of mini_magick. Eventually the morgify gets stuck in an infinite look. I've taken care of it by having a daemon watch the morgify process if it get's out of control, but was wondering if there was a better solution You can see the same *.gif being uploading in quick succession. I tried downloading this file too, and it isn't even a gif. I don't know what it is (I can't open it). Anyone experience this kind of exploit before?

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  • Class Issue (The type XXX is already defined )

    - by Android Stack
    I have listview app exploring cities each row point to diffrent city , in each city activity include button when clicked open new activity which is infinite gallery contains pics of that city , i add infinite gallery to first city and work fine , when i want to add it to the second city , it gave me red mark error in the class as follow : 1- The type InfiniteGalleryAdapter is already defined. 2-The type InfiniteGallery is already defined. i tried to change class name with the same result ,i delete R.jave and eclipse rebuild it with same result also i uncheck the java builder from project properties ,get same red mark error. please any help and advice will be appreciated thanks My Code : public class SecondCity extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); Boolean customTitleSupported = requestWindowFeature(Window.FEATURE_CUSTOM_TITLE); // Set the layout to use setContentView(R.layout.main); if (customTitleSupported) { getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE,R.layout.custom_title); TextView tv = (TextView) findViewById(R.id.tv); Typeface face=Typeface.createFromAsset(getAssets(),"BFantezy.ttf"); tv.setTypeface(face); tv.setText("MY PICTURES"); } InfiniteGallery galleryOne = (InfiniteGallery) findViewById(R.id.galleryOne); galleryOne.setAdapter(new InfiniteGalleryAdapter(this)); } } class InfiniteGalleryAdapter extends BaseAdapter { **//red mark here (InfiniteGalleryAdapter)** private Context mContext; public InfiniteGalleryAdapter(Context c, int[] imageIds) { this.mContext = c; } public int getCount() { return Integer.MAX_VALUE; } public Object getItem(int position) { return position; } public long getItemId(int position) { return position; } private LayoutInflater inflater=null; public InfiniteGalleryAdapter(Context a) { this.mContext = a; inflater = (LayoutInflater)mContext.getSystemService ( Context.LAYOUT_INFLATER_SERVICE); } public class ViewHolder{ public TextView text; public ImageView image; } private int[] images = { R.drawable.pic_1, R.drawable.pic_2, R.drawable.pic_3, R.drawable.pic_4, R.drawable.pic_5 }; private String[] name = { "This is first picture (1) " , "This is second picture (2)", "This is third picture (3)", "This is fourth picture (4)", " This is fifth picture (5)", }; public View getView(int position, View convertView, ViewGroup parent) { ImageView i = getImageView(); int itemPos = (position % images.length); try { i.setImageResource(images[itemPos]); ((BitmapDrawable) i.getDrawable()). setAntiAlias (true); } catch (OutOfMemoryError e) { Log.e("InfiniteGalleryAdapter", "Out of memory creating imageview. Using empty view.", e); } View vi=convertView; ViewHolder holder; if(convertView==null){ vi = inflater.inflate(R.layout.gallery_items, null); holder=new ViewHolder(); holder.text=(TextView)vi.findViewById(R.id.textView1); holder.image=(ImageView)vi.findViewById(R.id.image); vi.setTag(holder); } else holder=(ViewHolder)vi.getTag(); holder.text.setText(name[itemPos]); final int stub_id=images[itemPos]; holder.image.setImageResource(stub_id); return vi; } private ImageView getImageView() { ImageView i = new ImageView(mContext); return i; } } class InfiniteGallery extends Gallery { **//red mark here (InfiniteGallery)** public InfiniteGallery(Context context) { super(context); init(); } public InfiniteGallery(Context context, AttributeSet attrs) { super(context, attrs); init(); } public InfiniteGallery(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); init(); } private void init(){ // These are just to make it look pretty setSpacing(25); setHorizontalFadingEdgeEnabled(false); } public void setResourceImages(int[] name){ setAdapter(new InfiniteGalleryAdapter(getContext(), name)); setSelection((getCount() / 2)); } }

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  • How do I stop a datagrid's first-row itemRenderer from instantiating/adding/initializing/etc twice?

    - by Michael Prescott
    In a Flex DataGrid's first row, the itemRenderer will initialize twice. Tracing the results reveals that the flex framework is possibly creating two instances of the first row's itemRenderer. In a more complex application, where the itemRenderer contains a data-bound ColorPicker, we're seeing an infinite loop occur because of this problem. Only the first row's itemRenderer is initialized twice. Is there a way to override flex's behavior and stop this from occurring? The following code demonstrates the problem: Main Application: <?xml version="1.0" encoding="utf-8"?> <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" initialize="on_initialize(event);"> <mx:Script> <![CDATA[ /** * This experiment shows how the first row's itemrenderer is instantiated/added/initialized twice. * We've never even noticed this before we found that a data-bound ColorPicker enters a infinite * loop when it is within an itemRenderer. */ import mx.collections.ArrayCollection; import mx.events.FlexEvent; private var dg_array:Array; private var dg_arrayCollection:ArrayCollection; private function on_initialize(event:FlexEvent):void { dg_array = new Array(); dg_arrayCollection = new ArrayCollection(); dg_arrayCollection.addItem("item 1"); dg_arrayCollection.addItem("item 2"); dg.dataProvider = dg_arrayCollection; } ]]> </mx:Script> <mx:DataGrid id="dg" width="100%" height="100%" rowCount="5"> <mx:columns> <mx:DataGridColumn headerText="Name" itemRenderer="SimpleItemRenderer"/> </mx:columns> </mx:DataGrid> </mx:Application> SimpleItemRenderer: <?xml version="1.0" encoding="utf-8"?> <mx:Canvas xmlns:mx="http://www.adobe.com/2006/mxml" width="400" height="300" initialize="//on_initialize(event);"> <mx:Script> <![CDATA[ import mx.events.FlexEvent; [Bindable] override public function set data(value:Object):void { _data = value; } override public function get data():Object { return _data; } private var _data:Object; private function on_initialize_textInput(event:FlexEvent):void { trace("initialize:event.target="+event.target+", " + _data); // runs twice, for the first item only } private function on_creationComplete_textInput(event:FlexEvent):void { trace("creationComplete:event.target="+event.target+", " + _data); // runs twice, for the first item only } ]]> </mx:Script> <mx:TextInput text="{data}" id="textInput" initialize="on_initialize_textInput(event);" creationComplete="on_creationComplete_textInput(event);"/> </mx:Canvas> Abbreviated Output: initialize:event.target=ItemRenderers0.dg...SimpleItemRenderer12.textInput, null initialize:event.target=ItemRenderers0.dg...SimpleItemRenderer24.textInput, null creationComplete:event.target=ItemRenderers0.dg...SimpleItemRenderer24.textInput, item 1 initialize:event.target=ItemRenderers0.dg...SimpleItemRenderer29.textInput, null creationComplete:event.target=ItemRenderers0.dg...SimpleItemRenderer29.textInput, item 2 creationComplete:event.target=ItemRenderers0.dg...SimpleItemRenderer12.textInput, item 1

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  • Is Fast Enumeration messing with my text output?

    - by Dan Ray
    Here I am iterating through an array of NSDictionary objects (inside the parsed JSON response of the EXCELLENT MapQuest directions API). I want to build up an HTML string to put into a UIWebView. My code says: for (NSDictionary *leg in legs ) { NSString *thisLeg = [NSString stringWithFormat:@"<br>%@ - %@", [leg valueForKey:@"narrative"], [leg valueForKey:@"distance"]]; NSLog(@"This leg's string is %@", thisLeg); [directionsOutput appendString:thisLeg]; } The content of directionsOutput (which is an NSMutableString) contains ALL the values for [leg valueForKey:@"narrative"], wrapped up in parens, followed by a hyphen, followed by all the parenthesized values for [leg valueForKey:@"distance"]. So I put in that NSLog call... and I get the same thing there! It appears that the for() is somehow batching up our output values as we iterate, and putting out the output only once. How do I make it not do this but instead do what I actually want, which is an iterative output as I iterate? Here's what NSLog gets. Yes, I know I need to figure out NSNumberFormatter. ;-) This leg's string is ( "Start out going NORTH on INFINITE LOOP.", "Turn LEFT to stay on INFINITE LOOP.", "Turn RIGHT onto N DE ANZA BLVD.", "Merge onto I-280 S toward SAN JOSE.", "Merge onto CA-87 S via EXIT 3A.", "Take the exit on the LEFT.", "Merge onto CA-85 S via EXIT 1A on the LEFT toward GILROY.", "Merge onto US-101 S via EXIT 1A on the LEFT toward LOS ANGELES.", "Take the CA-152 E/10TH ST exit, EXIT 356.", "Turn LEFT onto CA-152/E 10TH ST/PACHECO PASS HWY. Continue to follow CA-152/PACHECO PASS HWY.", "Turn SLIGHT RIGHT.", "Turn SLIGHT RIGHT onto PACHECO PASS HWY/CA-152 E. Continue to follow CA-152 E.", "Merge onto I-5 S toward LOS ANGELES.", "Take the CA-46 exit, EXIT 278, toward LOST HILLS/WASCO.", "Turn LEFT onto CA-46/PASO ROBLES HWY. Continue to follow CA-46.", "Merge onto CA-99 S toward BAKERSFIELD.", "Merge onto CA-58 E via EXIT 24 toward TEHACHAPI/MOJAVE.", "Merge onto I-15 N via the exit on the LEFT toward I-40/LAS VEGAS.", "Keep RIGHT to take I-40 E via EXIT 140A toward NEEDLES (Passing through ARIZONA, NEW MEXICO, TEXAS, OKLAHOMA, and ARKANSAS, then crossing into TENNESSEE).", "Merge onto I-40 E via EXIT 12C on the LEFT toward NASHVILLE (Crossing into NORTH CAROLINA).", "Merge onto I-40 BR E/US-421 S via EXIT 188 on the LEFT toward WINSTON-SALEM.", "Take the CLOVERDALE AVE exit, EXIT 4.", "Turn LEFT onto CLOVERDALE AVE SW.", "Turn SLIGHT LEFT onto N HAWTHORNE RD.", "Turn RIGHT onto W NORTHWEST BLVD.", "1047 W NORTHWEST BLVD is on the LEFT." ) - ( 0.0020000000949949026, 0.07800000160932541, 0.14000000059604645, 7.827000141143799, 5.0329999923706055, 0.15299999713897705, 5.050000190734863, 20.871000289916992, 0.3050000071525574, 2.802999973297119, 0.10199999809265137, 37.78000259399414, 124.50700378417969, 0.3970000147819519, 25.264001846313477, 20.475000381469727, 125.8580093383789, 4.538000106811523, 1693.0350341796875, 628.8970336914062, 3.7990000247955322, 0.19099999964237213, 0.4099999964237213, 0.257999986410141, 0.5170000195503235, 0 )

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  • 42 passed to TerminateProcess, sometimes GetExitCodeProcess returns 0

    - by Emil
    After I get a handle returned by CreateProcess, I call TerminateProcess, passing 42 for the process exit code. Then, I use WaitForSingleObject for the process to terminate, and finally I call GetExitCodeProcess. None of the function calls report errors. The child process is an infinite loop and does not terminate on its own. The problem is that sometimes GetExitCodeProcess returns 42 for the exit code (as it should) and sometimes it returns 0. Any idea why? #include <string> #include <sstream> #include <iostream> #include <assert.h> #include <windows.h> void check_call( bool result, char const * call ); #define CHECK_CALL(call) check_call(call,#call); int main( int argc, char const * argv[] ) { if( argc>1 ) { assert( !strcmp(argv[1],"inf") ); for(;;) { } } int err=0; for( int i=0; i!=200; ++i ) { STARTUPINFO sinfo; ZeroMemory(&sinfo,sizeof(STARTUPINFO)); sinfo.cb=sizeof(STARTUPINFO); PROCESS_INFORMATION pe; char cmd_line[32768]; strcat(strcpy(cmd_line,argv[0])," inf"); CHECK_CALL((CreateProcess(0,cmd_line,0,0,TRUE,0,0,0,&sinfo,&pe)!=0)); CHECK_CALL((CloseHandle(pe.hThread)!=0)); CHECK_CALL((TerminateProcess(pe.hProcess,42)!=0)); CHECK_CALL((WaitForSingleObject(pe.hProcess,INFINITE)==WAIT_OBJECT_0)); DWORD ec=0; CHECK_CALL((GetExitCodeProcess(pe.hProcess,&ec)!=0)); CHECK_CALL((CloseHandle(pe.hProcess)!=0)); err += (ec!=42); } std::cout << err; return 0; } std::string get_last_error_str( DWORD err ) { std::ostringstream s; s << err; LPVOID lpMsgBuf=0; if( FormatMessageA( FORMAT_MESSAGE_ALLOCATE_BUFFER|FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_IGNORE_INSERTS, 0, err, MAKELANGID(LANG_NEUTRAL,SUBLANG_DEFAULT), (LPSTR)&lpMsgBuf, 0, 0) ) { assert(lpMsgBuf!=0); std::string msg; try { std::string((LPCSTR)lpMsgBuf).swap(msg); } catch( ... ) { } LocalFree(lpMsgBuf); if( !msg.empty() && msg[msg.size()-1]=='\n' ) msg.resize(msg.size()-1); if( !msg.empty() && msg[msg.size()-1]=='\r' ) msg.resize(msg.size()-1); s << ", \"" << msg << '"'; } return s.str(); } void check_call( bool result, char const * call ) { assert(call && *call); if( !result ) { std::cerr << call << " failed.\nGetLastError:" << get_last_error_str(GetLastError()) << std::endl; exit(2); } }

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  • Adjust parameters of serial port reading

    - by clinisbut
    Hello. I'm facing a particular issue that regards serial communication under win32. I'm communicating with a device can only accept frames when it is not already communicating. So I must find a valid frame and then inmediatelly send my request. I developed a class named Serial that handles basic operations on serial port (open, close, read, write) and then a Thread calls inside a loop read and write functions. Thread loop //Device is an object of class Serial while( device->isOpen() && !terminate ) { unsigned int readed = 0; unsigned long error = ERROR_SUCCESS; unsigned char* data = device->read( &readed, &error ); if( error==ERROR_SUCCESS ) { //If data received, deliver to upper level if( readed>0 ) { QByteArray output( (const char*)data, (signed int)readed ); emit dataArrived( output, readed ); } } else { //unrelated stuff } //Here I manage the writting issue //Only when nothing is received, and Upper layer wants to send a frame //(Upper layer only will mark as something to send when it detects a valid frame) if( readed==0 ) { out_lock.lock(); //If something to send... if( something_to_send > 0 ) { if( device->write( output_buffer, output_size, &error ) ) { //things... } } } } The Thread basically keeps reading, and when nothing is received, sees if somebody has signaled to send a frame (this means that a valid frame is just received). When this happens, it writes the frame through serial port. Here comes my problem. Inside the Serial::read() function: I use the overlapped way of reading: ::ClearCommError( handle, &dwErrors, &stat); if( stat.cbInQue ) { //If there's something to read, read it, please note the bytes to read parameter, here 1. bool ok = ::ReadFile( handle, buffer_in, 1, &bytes_read, &ov_reader ); if( !ok ) { DWORD _error = ::GetLastError(); if( _error == ERROR_IO_PENDING ) { DWORD result = ::WaitForMultipleObjects( 2, waiters, FALSE,INFINITE ); switch( result ) { //Eventshutdown case WAIT_OBJECT_0: /*code omitted*/break; case WAIT_OBJECT_0+1: ok = ::GetOverlappedResult( handle, &ov_reader, &bytes_read, true ); //check ok value omitted break; } } } } if( bytes_read>0 ) { *size = bytes_read; } Here starts my problem. When device sends me small frames (around 30 bytes) everything works fine, but when larger frames are sent, the code is not able to find any free time between frames causing the thread to never be able send any frame because readed is never 0. If I increase the number of bytes to read inside the read() function, lose the ability to detect when the device "listens": bool ok = ::ReadFile(handle, buffer_in, 50, &bytes_read, &ov_reader ); This happens because my app can receive the end of a frame together with the start of the next one. This behaviour is very common. In the other hand, if I change the INFINITE argument by a valid timeout in the WaitForMultipleObjects function, I lose data. So my question basically is... what I'm doing wrong? Why when reading 1 byte each time I don't find any free time to send my own frames? Thank you

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  • Problems with Asynchronous UDP Sockets

    - by ihatenetworkcoding
    Hi, I'm struggling a bit with socket programming (something I'm not at all familiar with) and I can't find anything which helps from google or MSDN (awful). Apologies for the length of this. Basically I have an existing service which recieves and responds to requests over UDP. I can't change this at all. I also have a client within my webapp which dispatches and listens for responses to that service. The existing client I've been given is a singleton which creates a socket and an array of response slots, and then creates a background thread with an infinite looping method that makes "sock.Receive()" calls and pushes the data received into the slot array. All kinds of things about this seem wrong to me and the infinite thread breaks my unit testing so I'm trying to replace this service with one which makes it's it's send/receives asynchronously instead. Point 1: Is this the right approach? I want a non-blocking, scalable, thread-safe service. My first attempt is roughly like this, which sort of worked but the data I got back was always shorter than expected (i.e. the buffer did not have the number of bytes requested) and seemed to throw exceptions when processed. private Socket MyPreConfiguredSocket; public object Query() { //build a request this.MyPreConfiguredSocket.SendTo(MYREQUEST, packet.Length, SocketFlags.Multicast, this._target); IAsyncResult h = this._sock.BeginReceiveFrom(response, 0, BUFFER_SIZE, SocketFlags.None, ref this._target, new AsyncCallback(ARecieve), this._sock); if (!h.AsyncWaitHandle.WaitOne(TIMEOUT)) { throw new Exception("Timed out"); } //process response data (always shortened) } private void ARecieve (IAsyncResult result) { int bytesreceived = (result as Socket).EndReceiveFrom(result, ref this._target); } My second attempt was based on more google trawling and this recursive pattern I frequently saw, but this version always times out! It never gets to ARecieve. public object Query() { //build a request this.MyPreConfiguredSocket.SendTo(MYREQUEST, packet.Length, SocketFlags.Multicast, this._target); State s = new State(this.MyPreConfiguredSocket); this.MyPreConfiguredSocket.BeginReceiveFrom(s.Buffer, 0, BUFFER_SIZE, SocketFlags.None, ref this._target, new AsyncCallback(ARecieve), s); if (!s.Flag.WaitOne(10000)) { throw new Exception("Timed out"); } //always thrown //process response data } private void ARecieve (IAsyncResult result) { //never gets here! State s = (result as State); int bytesreceived = s.Sock.EndReceiveFrom(result, ref this._target); if (bytesreceived > 0) { s.Received += bytesreceived; this._sock.BeginReceiveFrom(s.Buffer, s.Received, BUFFER_SIZE, SocketFlags.None, ref this._target, new AsyncCallback(ARecieve), s); } else { s.Flag.Set(); } } private class State { public State(Socket sock) { this._sock = sock; this._buffer = new byte[BUFFER_SIZE]; this._buffer.Initialize(); } public Socket Sock; public byte[] Buffer; public ManualResetEvent Flag = new ManualResetEvent(false); public int Received = 0; } Point 2: So clearly I'm getting something quite wrong. Point 3: I'm not sure if I'm going about this right. How does the data coming from the remote service even get to the right listening thread? Do I need to create a socket per request? Out of my comfort zone here. Need help.

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  • TFS 2010 Build Custom Activity for Merging Assemblies

    - by Jakob Ehn
    *** The sample build process template discussed in this post is available for download from here: http://cid-ee034c9f620cd58d.office.live.com/self.aspx/BlogSamples/ILMerge.xaml ***   In my previous post I talked about library builds that we use to build and replicate dependencies between applications in TFS. This is typically used for common libraries and tools that several other application need to reference. When the libraries grow in size over time, so does the number of assemblies. So all solutions that uses the common library must reference all the necessary assemblies that they need, and if we for example do a refactoring and extract some code into a new assembly, all the clients must update their references to reflect these changes, otherwise it won’t compile. To improve on this, we use a tool from Microsoft Research called ILMerge (Download from here). It can be used to merge several assemblies into one assembly that contains all types. If you haven’t used this tool before, you should check it out. Previously I have implemented this in builds using a simple batch file that contains the full command, something like this: "%ProgramFiles(x86)%\microsoft\ilmerge\ilmerge.exe" /target:library /attr:ClassLibrary1.bl.dll /out:MyNewLibrary.dll ClassLibrary1.dll ClassLibrar2.dll ClassLibrary3.dll This merges 3 assemblies (ClassLibrary1, 2 and 3) into a new assembly called MyNewLibrary.dll. It will copy the attributes (file version, product version etc..) from ClassLibrary1.dll, using the /attr switch. For more info on ILMerge command line tool, see the above link. This approach works, but requires a little bit too much knowledge for the developers creating builds, therefor I have implemented a custom activity that wraps the use of ILMerge. This makes it much simpler to setup a new build definition and have the build automatically do the merging. The usage of the activity is then implemented as part of the Library Build process template mentioned in the previous post. For this article I have just created a simple build process template that only performs the ILMerge operation.   Below is the code for the custom activity. To make it compile, you need to reference the ILMerge.exe assembly. /// <summary> /// Activity for merging a list of assembies into one, using ILMerge /// </summary> public sealed class ILMergeActivity : BaseCodeActivity { /// <summary> /// A list of file paths to the assemblies that should be merged /// </summary> [RequiredArgument] public InArgument<IEnumerable<string>> InputAssemblies { get; set; } /// <summary> /// Full path to the generated assembly /// </summary> [RequiredArgument] public InArgument<string> OutputFile { get; set; } /// <summary> /// Which input assembly that the attibutes for the generated assembly should be copied from. /// Optional. If not specified, the first input assembly will be used /// </summary> public InArgument<string> AttributeFile { get; set; } /// <summary> /// Kind of assembly to generate, dll or exe /// </summary> public InArgument<TargetKindEnum> TargetKind { get; set; } // If your activity returns a value, derive from CodeActivity<TResult> // and return the value from the Execute method. protected override void Execute(CodeActivityContext context) { string message = InputAssemblies.Get(context).Aggregate("", (current, assembly) => current + (assembly + " ")); TrackMessage(context, "Merging " + message + " into " + OutputFile.Get(context)); ILMerge m = new ILMerge(); m.SetInputAssemblies(InputAssemblies.Get(context).ToArray()); m.TargetKind = TargetKind.Get(context) == TargetKindEnum.Dll ? ILMerge.Kind.Dll : ILMerge.Kind.Exe; m.OutputFile = OutputFile.Get(context); m.AttributeFile = !String.IsNullOrEmpty(AttributeFile.Get(context)) ? AttributeFile.Get(context) : InputAssemblies.Get(context).First(); m.SetTargetPlatform(RuntimeEnvironment.GetSystemVersion().Substring(0,2), RuntimeEnvironment.GetRuntimeDirectory()); m.Merge(); TrackMessage(context, "Generated " + m.OutputFile); } } [Browsable(true)] public enum TargetKindEnum { Dll, Exe } NB: The activity inherits from a BaseCodeActivity class which is an internal helper class which contains some methods and properties useful for moste custom activities. In this case, it uses the TrackeMessage method for writing to the build log. You either need to remove the TrackMessage method calls, or implement this yourself (which is not very hard… ) The custom activity has the following input arguments: InputAssemblies A list with the (full) paths to the assemblies to merge OutputFile The name of the resulting merged assembly AttributeFile Which assembly to use as the template for the attribute of the merged assembly. This argument is optional and if left blank, the first assembly in the input list is used TargetKind Decides what type of assembly to create, can be either a dll or an exe Of course, there are more switches to the ILMerge.exe, and these can be exposed as input arguments as well if you need it. To show how the custom activity can be used, I have attached a build process template (see link at the top of this post) that merges the output of the projects being built (CommonLibrary.dll and CommonLibrary2.dll) into a merged assembly (NewLibrary.dll). The build process template has the following custom process parameters:   The Assemblies To Merge argument is passed into a FindMatchingFiles activity to located all assemblies that are located in the BinariesDirectory folder after the compilation has been performed by Team Build. Here is the complete sequence of activities that performs the merge operation. It is located at the end of the Try, Compile, Test and Associate… sequence: It splits the AssembliesToMerge parameter and appends the full path (using the BinariesDirectory variable) and then enumerates the matching files using the FindMatchingFiles activity. When running the build, you can see that it merges two assemblies into a new one:     And the merged assembly (and associated pdb file) is copied to the drop location together with the rest of the assemblies:

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  • Ubuntu 12.04 LTS Wireless Asus USB-N53 (rt3572sta) driver installation issue

    - by Jake Thompson
    My purchase of the Asus USB-N53 just came in today and I spent several hours Googling and researching drivers for this device. When I first plugged the device in it connected fine to my open system, WEP, DHCP configured access point. I opened Google Chrome and a few pages loaded, everything seemed fine. 30 seconds later... Boom! It disconnected and showed attempts to reconnect and asked for the WEP key and just showed a state of infinite connection time until it asked me for the password again. I'm using amd64 (64 bit Ubuntu desktop 12.04 LTS) The official driver can be found here although I had no luck with it. lsusb: Bus 003 Device 002: ID 0b05:179d ASUSTek Computer, Inc. uname -a Linux Jake 3.2.0-31-generic #50-Ubuntu SMP Fri Sep 7 16:16:45 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux ----------------------------------------------------------------------------------Solved: I must of done something wrong when I originally installed the latest drivers from the chipset manufacturers website. I tried reinstalling and did modprobe rt3572sta and waited maybe 10 minutes??? and I connected then I rebooted and everything seems to be working so far. What I did do before hand is unplug the device and typed into the terminal (once for every source I attempted to install): cd '<directory of the driver source>' make uninstall make clean Then I went into the 2.5.0.0 directory and installed that with make make install Then I typed modprobe rt3572sta This was all in superuser. For those who don't know: sudo su

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  • MetroTwit is a Sleek Native Twitter Client for Your Windows System

    - by Asian Angel
    Do you love the new Metro design and need a native Twitter desktop client for your Windows system too? Then you may want to have a look at MetroTwit. When you kick-start the MetroTwit exe file it will download the necessary .NET Framework components if you do not already have them installed. Once that is finished it will then download the MetroTwit installation files to ensure that you have the latest release. MetroTwit will automatically start once the setup process has finished. From there you can quickly modify the layout (i.e. visible columns, etc.), theme, and other UI features to make MetroTwit right at home on your system. UI features visible in the screenshot above: Top: Access the Settings in the center at the top of the window Bottom: Add Column, Lists, Refresh, Tweet Window, Search Twitter, User Profile, and Twitter Trends As you can see here the Settings are laid out nicely and very easy to navigate through. Features of MetroTwit: Drag and drop image support TwitLonger support for longer tweets Tweet breadcrumbs Infinite scrolling Auto-complete for user names and hashtags Themes and accents Resizable and reorderable columns What The Trend access URL shortening and previews Windows 7 Taskbar integration Quick-glance notifications Flawless high DPI support Note: Requires .NET Framework 4.0. Download MetroTwit [via DownloadSquad] Latest Features How-To Geek ETC What Can Super Mario Teach Us About Graphics Technology? Windows 7 Service Pack 1 is Released: But Should You Install It? How To Make Hundreds of Complex Photo Edits in Seconds With Photoshop Actions How to Enable User-Specific Wireless Networks in Windows 7 How to Use Google Chrome as Your Default PDF Reader (the Easy Way) How To Remove People and Objects From Photographs In Photoshop MetroTwit is a Sleek Native Twitter Client for Your Windows System Make Efficient Use of Tab Bar Space by Customizing Tab Width in Firefox See the Geeky Work Done Behind the Scenes to Add Sounds to Movies [Video] Use a Crayon to Enhance Engraved Lettering on Electronics Adult Swim Brings Their Programming Lineup to iOS Devices Feel the Chill of the South Atlantic with the Antarctica Theme for Windows 7

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  • CodeCritics.com: A no nonsense place for coders to critique code and raise awareness of standards and "good coding standards" [closed]

    - by Visionary Software Solutions
    StackOverflow has been a boon for increasing programming knowledge by allowing developers to ask for help and knowledge related to programming. Oftentimes these questions boil down to: This code is broken, fix it I don't know how to do this Is this the best approach (hard question to answer on StackExchange, but democratic) Oftentimes, however, these questions are discussed at a very high level. "I use web services with a proxy client to ..." But, as Grady Booch is fond of saying "the Truth is raw, naked, running code". Those high level descriptions can be accomplished in any ways. Programming is an Art, and there are an infinite number of different ways to do things. But some are better than others. A site devoted to Q&A can help increase knowledge...a site devoted to critique of code can help elevate standards and result in higher quality knowledge. By upvoting the most elegant ways to solve a short, concise problem statement, or just looking at a piece of code and saying "this is ugly, how can we fix it?" we can increase community participation in discussions about the substantive details of an approach: "is my commenting clear? "Is this 3 nested for-loops with a continue that breaks in a special case a good way of building an object?" "Does this extremely generic and polymorphic inheritance hierarchy have issues?") Code is an art/craft and science/engineering artifact. Doesn't it deserve the same type of review treatment as a painting and an experiment? For praising those that provide that moment of zen when looking at exceptionally good code that makes you believe in a better tomorrow, and panning those whose offal is so offensive that were you to meet them on the job you'd say "YOU! GET OUT!!!" Hence, CodeCritics. A collaborative critiquing platform in the style of StackOverflow focused solely on critiquing code that can act as a collaborative code review and assist in the discovery of Design Patterns.

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  • Oracle Open World 2013 - JD Edwards at Your Fingertips

    - by KemButller
    The Oracle & JD Edwards Universe at Your Fingertips!  Oracle Open World features thousands of sessions from which attendees can choose, including keynotes, technical sessions, demos, and hands-on labs. Hundreds of exhibitors will be on hand to share what they’re bringing to the leading edge of Oracle technology. You will have an infinite number of opportunities to network, trade information with peers, and gain insights from experts. For JD Edwards’ customers this valuable experience is twofold. Enjoy the convenience of attending the core JD Edwards’ program featured at the Intercontinental Hotel and experience the keynotes, educational sessions, networking events and partner solutions exhibited at the adjacent Moscone Convention Center.  Highlights for JD Edwards Customers:  Kickoff with the JD Edwards General Session, followed by product strategy road map sessions.  Select from over 60 educational sessions specifically applicable to JD Edwards.  Deepen your knowledge by attending the JD Edwards EnterpriseOne technical hands on lab sessions including: o One View Reporting – basic and advanced o EnterpriseOne Page Generator o User Interface Personalization o Configuring Composite Applications with Café One  Chose from thousands of educational sessions offered throughout the entire conference covering Oracle applications, industries, middleware, server and storage systems and database.  Meet the JD Edwards experts in the Oracle DEMOGrounds and get hands on experience with the latest and hottest features in Applications, Tools and Technologies, Mobility, In-Memory Applications, Health and Safety Incident Management, User Experience and Reporting.  Visit the JD Edwards Partner Pavilion at the Intercontinental Hotel featuring partner organizations with solutions for JD Edwards’ customers.  Meet with the Oracle JD Edwards Upgrade team during the conference as part of the Upgrade Care Program. Maximize your conference experience and leave with the information and contacts you need to turbo-charge your upgrade planning. Contact Barbara.canham-AT-oracle-DOT-com prior to the conference for more information.  Arrive on Sunday to participate in sessions presented by the Special Interest Groups of Quest International User Group. Oracle OpenWorld

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  • SQL SERVER – Weekly Series – Memory Lane – #032

    - by Pinal Dave
    Here is the list of selected articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2007 Complete Series of Database Coding Standards and Guidelines SQL SERVER Database Coding Standards and Guidelines – Introduction SQL SERVER – Database Coding Standards and Guidelines – Part 1 SQL SERVER – Database Coding Standards and Guidelines – Part 2 SQL SERVER Database Coding Standards and Guidelines Complete List Download Explanation and Example – SELF JOIN When all of the data you require is contained within a single table, but data needed to extract is related to each other in the table itself. Examples of this type of data relate to Employee information, where the table may have both an Employee’s ID number for each record and also a field that displays the ID number of an Employee’s supervisor or manager. To retrieve the data tables are required to relate/join to itself. Insert Multiple Records Using One Insert Statement – Use of UNION ALL This is very interesting question I have received from new developer. How can I insert multiple values in table using only one insert? Now this is interesting question. When there are multiple records are to be inserted in the table following is the common way using T-SQL. Function to Display Current Week Date and Day – Weekly Calendar Straight blog post with script to find current week date and day based on the parameters passed in the function.  2008 In my beginning years, I have almost same confusion as many of the developer had in their earlier years. Here are two of the interesting question which I have attempted to answer in my early year. Even if you are experienced developer may be you will still like to read following two questions: Order Of Column In Index Order of Conditions in WHERE Clauses Example of DISTINCT in Aggregate Functions Have you ever used DISTINCT with the Aggregation Function? Here is a simple example about how users can do it. Create a Comma Delimited List Using SELECT Clause From Table Column Straight to script example where I explained how to do something easy and quickly. Compound Assignment Operators SQL SERVER 2008 has introduced new concept of Compound Assignment Operators. Compound Assignment Operators are available in many other programming languages for quite some time. Compound Assignment Operators is operator where variables are operated upon and assigned on the same line. PIVOT and UNPIVOT Table Examples Here is a very interesting question – the answer to the question can be YES or NO both. “If we PIVOT any table and UNPIVOT that table do we get our original table?” Read the blog post to get the explanation of the question above. 2009 What is Interim Table – Simple Definition of Interim Table The interim table is a table that is generated by joining two tables and not the final result table. In other words, when two tables are joined they create an interim table as resultset but the resultset is not final yet. It may be possible that more tables are about to join on the interim table, and more operations are still to be applied on that table (e.g. Order By, Having etc). Besides, it may be possible that there is no interim table; sometimes final table is what is generated when the query is run. 2010 Stored Procedure and Transactions If Stored Procedure is transactional then, it should roll back complete transactions when it encounters any errors. Well, that does not happen in this case, which proves that Stored Procedure does not only provide just the transactional feature to a batch of T-SQL. Generate Database Script for SQL Azure When talking about SQL Azure the most common complaint I hear is that the script generated from stand-along SQL Server database is not compatible with SQL Azure. This was true for some time for sure but not any more. If you have SQL Server 2008 R2 installed you can follow the guideline below to generate a script which is compatible with SQL Azure. Convert IN to EXISTS – Performance Talk It is NOT necessary that every time when IN is replaced by EXISTS it gives better performance. However, in our case listed above it does for sure give better performance. You can read about this subject in the associated blog post. Subquery or Join – Various Options – SQL Server Engine Knows the Best Every single time whenever there is a performance tuning exercise, I hear the conversation from developer where some prefer subquery and some prefer join. In this two part blog post, I explain the same in the detail with examples. Part 1 | Part 2 Merge Operations – Insert, Update, Delete in Single Execution MERGE is a new feature that provides an efficient way to do multiple DML operations. In earlier versions of SQL Server, we had to write separate statements to INSERT, UPDATE, or DELETE data based on certain conditions; however, at present, by using the MERGE statement, we can include the logic of such data changes in one statement that even checks when the data is matched and then just update it, and similarly, when the data is unmatched, it is inserted. 2011 Puzzle – Statistics are not updated but are Created Once Here is the quick scenario about my setup. Create Table Insert 1000 Records Check the Statistics Now insert 10 times more 10,000 indexes Check the Statistics – it will be NOT updated – WHY? Question to You – When to use Function and When to use Stored Procedure Personally, I believe that they are both different things - they cannot be compared. I can say, it will be like comparing apples and oranges. Each has its own unique use. However, they can be used interchangeably at many times and in real life (i.e., production environment). I have personally seen both of these being used interchangeably many times. This is the precise reason for asking this question. 2012 In year 2012 I had two interesting series ran on the blog. If there is no fun in learning, the learning becomes a burden. For the same reason, I had decided to build a three part quiz around SEQUENCE. The quiz was to identify the next value of the sequence. I encourage all of you to take part in this fun quiz. Guess the Next Value – Puzzle 1 Guess the Next Value – Puzzle 2 Guess the Next Value – Puzzle 3 Guess the Next Value – Puzzle 4 Simple Example to Configure Resource Governor – Introduction to Resource Governor Resource Governor is a feature which can manage SQL Server Workload and System Resource Consumption. We can limit the amount of CPU and memory consumption by limiting /governing /throttling on the SQL Server. If there are different workloads running on SQL Server and each of the workload needs different resources or when workloads are competing for resources with each other and affecting the performance of the whole server resource governor is a very important task. Tricks to Replace SELECT * with Column Names – SQL in Sixty Seconds #017 – Video  Retrieves unnecessary columns and increases network traffic When a new columns are added views needs to be refreshed manually Leads to usage of sub-optimal execution plan Uses clustered index in most of the cases instead of using optimal index It is difficult to debug SQL SERVER – Load Generator – Free Tool From CodePlex The best part of this SQL Server Load Generator is that users can run multiple simultaneous queries again SQL Server using different login account and different application name. The interface of the tool is extremely easy to use and very intuitive as well. A Puzzle – Swap Value of Column Without Case Statement Let us assume there is a single column in the table called Gender. The challenge is to write a single update statement which will flip or swap the value in the column. For example if the value in the gender column is ‘male’ swap it with ‘female’ and if the value is ‘female’ swap it with ‘male’. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Great Debugging skills weak problem solving

    - by Mahmoud
    For the 5 years I worked for various companies, I worked in large software like computer vision kits, embedded, games. I found myself very good at debuggins skills, I've even found and fixed bugs in frameworks and I solved them. The problem is that I'm very weak at problem solving. I got interview with Qualcomm, and they said you're fine at software, but you have a limited problem solving, I also had the same results with Google. I'm very bad at solving puzzles and brain teasers. During the interviews I solve all of the software related problems on the blackboard, but when I went to the GM and face math problems and probabilities, I struggle. How can I improve my problem solving skills? Edit Some of the problems: A cake that is cut from anywhere and needs just one cut to halved in equal. I told him cut it horizontally, he said No, consider it as a 2D Problem!. Consider a concenteric 3 circles, each one can get a color, but not matched with the other circle, how many blobs you can make out of those circles ? this was with the GM ( Augmented Reality SDK) Consider a train, an infinite one, and you looked at the window, and there are two cars, one big, and one small, what is the probability of having only a big car, I said 50%, he said, what if that two cars you dont know their length, and you want to get the probability of getting the biggest one, I struggled, didn't solve it... I was really exahusted after long day of interviews prob of having a number divisible by 5 in numbers from 1 to 100.. struggled!! All coding questions I solved them like reverse a string, detect a cycle in a linked list,..etc.

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  • Correct For Loop Design

    - by Yttrill
    What is the correct design for a for loop? Felix currently uses if len a > 0 do for var i in 0 upto len a - 1 do println a.[i]; done done which is inclusive of the upper bound. This is necessary to support the full range of values of a typical integer type. However the for loop shown does not support zero length arrays, hence the special test, nor will the subtraction of 1 work convincingly if the length of the array is equal to the number of integers. (I say convincingly because it may be that 0 - 1 = maxval: this is true in C for unsigned int, but are you sure it is true for unsigned char without thinking carefully about integral promotions?) The actual implementation of the for loop by my compiler does correctly handle 0 but this requires two tests to implement the loop: continue: if not (i <= bound) goto break body if i == bound goto break ++i goto continue break: Throw in the hand coded zero check in the array example and three tests are needed. If the loop were exclusive it would handle zero properly, avoiding the special test, but there'd be no way to express the upper bound of an array with maximum size. Note the C way of doing this: for(i=0; predicate(i); increment(i)) has the same problem. The predicate is tested after the increment, but the terminating increment is not universally valid! There is a general argument that a simple exclusive loop is enough: promote the index to a large type to prevent overflow, and assume no one will ever loop to the maximum value of this type.. but I'm not entirely convinced: if you promoted to C's size_t and looped from the second largest value to the largest you'd get an infinite loop!

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  • What have you learnt that has a steep learning curve?

    - by Jonathan Khoo
    Recently, I've invested time in learning the intricacies of Git and it has got me thinking about time and learning. (My previous experience with version control systems was only limited use of CVS and SVN.) It took me a whole day's worth of reading to be able to understand the concepts and differences of Git. There are an infinite number of things available for us to learn. Some, more useful than others. I don't know Fortran - I'm relatively young. But looking back at the preceding years of my life, I notice that I'm busier and busier as time goes on. The amount of things I have to get through in a day is increasingly out of my control. It doesn't take a genius to extrapolate that information and realise I'll have even less time in the future - unless I get fired, but I have no strong plans relating to that idea for now. So, given that I have much more time and energy now than I will have in the future: what have you learnt, that has a steep learning curve, that you would possibly recommend to a fellow programmer? Edit: I've stumbled upon the excellent question What programming skills have provided you the best return on investment? and hav realised that my way of approaching how to spend learning time was naive - it doesn't matter if ten useful concepts can be learnt in the time of one if they're worth it.

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