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  • C Run-Time library part 2

    - by b-gen-jack-o-neill
    Hi, I was suggested when I have some further questions on my older ones, to create newer Question and reffer to old one. So, this is the original question: What is the C runtime library? OK, from your answers, I now get thet statically linked libraries are Microsoft implementation of C standart functions. Now: If I get it right, the scheme would be as follow: I want to use printf(), so I must include which just tels compiler there us functio printf() with these parameters. Now, when I compile code, becouse printf() is defined in C Standart Library, and becouse Microsoft decided to name it C Run Time library, it gets automatically statically linked from libcmt.lib (if libcmt.lib is set in compiler) at compile time. I ask, becouse on wikipedia, in article about runtime library there is that runtime library is linked in runtime, but .lib files are linked at compile time, am I right? Now, what confuses me. There is .dll version of C standart library. But I thought that to link .dll file, you must actually call winapi program to load that library. So, how can be these functions dynamically linked, if there is no static library to provide code to tell Windows to load desired functions from dll? And really last question on this subject - are C Standart library functions also calls to winapi even they are not .dll files like more advanced WinAPI functions? I mean, in the end to access framebuffer and print something you must tell Windows to do it, since OS cannot let you directly manipulate HW. I think of it like the OS must be written to support all C standart library functions same way across similiar versions, since they are statically linked, and can differently support more complex WinAPI calls becouse new version of OS can have adjustements in the .dll file.

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  • Asymptotic runtime of list-to-tree function

    - by Deestan
    I have a merge function which takes time O(log n) to combine two trees into one, and a listToTree function which converts an initial list of elements to singleton trees and repeatedly calls merge on each successive pair of trees until only one tree remains. Function signatures and relevant implementations are as follows: merge :: Tree a -> Tree a -> Tree a --// O(log n) where n is size of input trees singleton :: a -> Tree a --// O(1) empty :: Tree a --// O(1) listToTree :: [a] -> Tree a --// Supposedly O(n) listToTree = listToTreeR . (map singleton) listToTreeR :: [Tree a] -> Tree a listToTreeR [] = empty listToTreeR (x:[]) = x listToTreeR xs = listToTreeR (mergePairs xs) mergePairs :: [Tree a] -> [Tree a] mergePairs [] = [] mergePairs (x:[]) = [x] mergePairs (x:y:xs) = merge x y : mergePairs xs This is a slightly simplified version of exercise 3.3 in Purely Functional Data Structures by Chris Okasaki. According to the exercise, I shall now show that listToTree takes O(n) time. Which I can't. :-( There are trivially ceil(log n) recursive calls to listToTreeR, meaning ceil(log n) calls to mergePairs. The running time of mergePairs is dependent on the length of the list, and the sizes of the trees. The length of the list is 2^h-1, and the sizes of the trees are log(n/(2^h)), where h=log n is the first recursive step, and h=1 is the last recursive step. Each call to mergePairs thus takes time (2^h-1) * log(n/(2^h)) I'm having trouble taking this analysis any further. Can anyone give me a hint in the right direction?

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  • Fastest way to convert a list of doubles to a unique list of integers?

    - by javanix
    I am dealing with a MySQL table here that is keyed in a somewhat unfortunate way. Instead of using an auto increment table as a key, it uses a column of decimals to preserve order (presumably so its not too difficult to insert new rows while preserving a primary key and order). Before I go through and redo this table to something more sane, I need to figure out how to rekey it without breaking everything. What I would like to do is something that takes a list of doubles (the current keys) and outputs a list of integers (which can be cast down to doubles for rekeying). For example, input {1.00, 2.00, 2.50, 2.60, 3.00} would give output {1, 2, 3, 4, 5). Since this is a database, I also need to be able to update the rows nicely: UPDATE table SET `key`='3.00' WHERE `key`='2.50'; Can anyone think of a speedy algorithm to do this? My current thought is to read all of the doubles into a vector, take the size of the vector, and output a new vector with values from 1 => doubleVector.size. This seems pretty slow, since you wouldn't want to read every value into the vector if, for instance, only the last n/100 elements needed to be modified. I think there is probably something I can do in place, since only values after the first non-integer double need to be modified, but I can't for the life of me figure anything out that would let me update in place as well. For instance, setting 2.60 to 3.00 the first time you see 2.50 in the original key list would result in an error, since the key value 3.00 is already used for the table.

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  • private class calling a method from its outer class

    - by oxinabox.ucc.asn.au
    Ok, so I have a class for a "Advanced Data Structure" (in this case a kinda tree) SO I implimented a Iterator as a private class with in it. So the iterator needs to implement a remove function to remove the last retuirned element. now my ADT already impliments a remove function, and in this case there is very little (thinking about it, i think nothing) to be gain by implimenting a different remove function for the iterator. so how do I go about calling the remove from my ADT sketch of my struture: public class ADT { ... private class ADT_Iterator impliments java.util.Itorator{ ... public void remove(){ //where I want to call the ADT's remove function from } ... public void remove( Object paramFoo ) { ... } ... } So just calling remove(FooInstance) won't work (will it?) and this.remove(FooInstance) is the same thing. what do i call? (and changign the name of the ADT's remove function is not an option, as that AD T has to meet an Interace wich I am note at liberty to change) I could make both of them call a removeHelper functon, I guess...

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  • python mongokit Connection() AssertionError

    - by zalew
    just installed mongokit and can't figure out why I get AssertionError python console: >>> from mongokit import Connection >>> c = Connection() Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/usr/local/lib/python2.6/dist-packages/mongokit-0.5.3-py2.6.egg/mongokit/connection.py", line 35, in __init__ super(Connection, self).__init__(*args, **kwargs) File "build/bdist.linux-i686/egg/pymongo/connection.py", line 169, in __init__ File "build/bdist.linux-i686/egg/pymongo/connection.py", line 338, in __find_master File "build/bdist.linux-i686/egg/pymongo/connection.py", line 226, in __master File "build/bdist.linux-i686/egg/pymongo/database.py", line 220, in command File "build/bdist.linux-i686/egg/pymongo/collection.py", line 356, in find_one File "build/bdist.linux-i686/egg/pymongo/cursor.py", line 485, in next File "build/bdist.linux-i686/egg/pymongo/cursor.py", line 461, in _refresh File "build/bdist.linux-i686/egg/pymongo/cursor.py", line 429, in __send_message File "build/bdist.linux-i686/egg/pymongo/helpers.py", line 98, in _unpack_response AssertionError >>> mongodb console: Wed Mar 31 10:27:34 connection accepted from 127.0.0.1:60480 #30 Wed Mar 31 10:27:34 end connection 127.0.0.1:60480 db 1.5 pymongo 1.5 (tested also on 1.4.) mongokit 0.5.3 (also 0.5.2)

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  • help('modules') crashing?

    - by Chris
    I was trying to install a module for opencv and added an opencv.pth file to the folder beyond my sites.py file. I have since deleted it and no change. When I try to run help('modules'), I get the following error: Please wait a moment while I gather a list of all available modules... /System/Library/Frameworks/Python.framework/Versions/2.5/Extras/lib/python/twisted/words/im/init.py:8: UserWarning: twisted.im will be undergoing a rewrite at some point in the future. warnings.warn("twisted.im will be undergoing a rewrite at some point in the future.") /System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/pkgutil.py:110: DeprecationWarning: The wxPython compatibility package is no longer automatically generated or actively maintained. Please switch to the wx package as soon as possible. import(name) Traceback (most recent call last): File "", line 1, in File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site.py", line 348, in call return pydoc.help(*args, **kwds) File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/pydoc.py", line 1644, in call self.help(request) File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/pydoc.py", line 1681, in help elif request == 'modules': self.listmodules() File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/pydoc.py", line 1802, in listmodules ModuleScanner().run(callback) File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/pydoc.py", line 1853, in run for importer, modname, ispkg in pkgutil.walk_packages(): File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/pkgutil.py", line 110, in walk_packages import(name) File "/BinaryCache/wxWidgets/wxWidgets-11~262/Root/System/Library/Frameworks/Python.framework/Versions/2.5/Extras/lib/python/wxaddons/init.py", line 180, in import_hook File "/Library/Python/2.5/site-packages/ctypes_opencv/init.py", line 19, in from ctypes_opencv.cv import * File "/BinaryCache/wxWidgets/wxWidgets-11~262/Root/System/Library/Frameworks/Python.framework/Versions/2.5/Extras/lib/python/wxaddons/init.py", line 180, in import_hook File "/Library/Python/2.5/site-packages/ctypes_opencv/cv.py", line 2567, in ('desc', CvMat_r, 1), # CvMat* desc File "/Library/Python/2.5/site-packages/ctypes_opencv/cxcore.py", line 114, in cfunc return CFUNCTYPE(result, *atypes)((name, dll), tuple(aflags)) AttributeError: dlsym(0x2674d10, cvCreateFeatureTree): symbol not found What gives?!

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  • QT QSslError being signaled with the error code set to NoError

    - by Nantucket
    My Problem I compiled OpenSSL into QT to enable OpenSSL support. Everything appeared to go correctly in the compile. However, when I try to use the official HTTP example application that can be found here, everytime I try to download an https page, it will signal two QSslError, each with contents NoError. The types of QSslErrors, including NoError, are documented here, poorly. There is no explanation on why they even included an error type called NoError, or what it means. Bizarrely, the NoError error code seems to be true, as it downloads the remote https document perfectly even while signaling the error. Does anyone have any idea what this means and what could possibly be causing it? Optional Background Reading Here is the relevant part of the code from the example app (this is connected to the network connection's sslErrors signal by the constructor): void HttpWindow::sslErrors(QNetworkReply*,const QList<QSslError> &errors) { QString errorString; foreach (const QSslError &error, errors) { if (!errorString.isEmpty()) errorString += ", "; errorString += error.errorString(); } if (QMessageBox::warning(this, tr("HTTP"), tr("One or more SSL errors has occurred: %1").arg(errorString), QMessageBox::Ignore | QMessageBox::Abort) == QMessageBox::Ignore) { reply->ignoreSslErrors(); } } I have tried the old version of this example, and it produced the same result. I have tried OpenSSL 1.0.0a and 0.9.8o. I have tried tried compiling OpenSSL myself, I have tried using pre-compiled versions of OpenSSL from the net. All produce the same result. If this were my first time using QT with SSL, I would almost think this is the intended result (even though their example application is popping up error warning message windows), if not for the fact that last time I played with QT, using what would now be an old version of QT with an old version of SSL, I distinctly remember everything working fine with no error windows. My system is running Windows 7 x64.

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  • Wireshark Dissector: How to Identify Missing UDP Frames?

    - by John Dibling
    How do you identify missing UDP frames in a custom Wireshark dissector? I have written a custom dissector for the CQS feed (reference page). One of our servers gaps when receiving this feed. According to Wireshark, some UDP frames are never received. I know that the frames were sent because all of our other servers are gap-free. A CQS frame consists of multiple messages, each having its own sequence number. My custom dissector provides the following data to Wireshark: cqs.frame_gaps - the number of gaps within a UDP frame (always zero) cqs.frame_first_seq - the first sequence number in a UDP frame cqs.frame_expected_seq - the first sequence number expected in the next UDP frame cqs.frame_msg_count - the number of messages in this UDP frame And I am displaying each of these values in custom columns, as shown in this screenshot: I tried adding code to my dissector that simply saves the last-processed sequence number (as a local static), and flags gaps when the dissector processes a frame where current_sequence != (previous_sequence + 1). This did not work because the dissector can be called in random-access order, depending on where you click in the GUI. So you could process frame 10, then frame 15, then frame 11, etc. Is there any way for my dissector to know if the frame that came before it (or the frame that follows) is missing? The dissector is written in C. (See also a companion post on serverfault.com)

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  • Yahoo Query Language Problem

    - by Damiano
    Hello everybody! Today, I've started with Yahoo Query Language. I would use it to retrive stocks details, so I'm talking about Yahoo Finance. I think there is a bug on this language. This is my query: select * from yahoo.finance.quoteslist where symbol='@^GSPC' I ALWAYS get 51 results! it's impossible, take a look at: http://it.finance.yahoo.com/q/cp?s=^GSPC There are 500 results! I also tried some paging parameters. select * from yahoo.finance.quoteslist(50,30) where symbol='@^GSPC' (to get from 50 to 80) select * from yahoo.finance.quoteslist(100) where symbol='@^GSPC' (to get the first 100 results) select * from yahoo.finance.quoteslist where symbol='@^GSPC' limit 30 offset 50 but ALWAYS the last stock is: <quote symbol="BBY"> <Symbol>BBY</Symbol> <LastTradePriceOnly>41.03</LastTradePriceOnly> <LastTradeDate>5/7/2010</LastTradeDate> <LastTradeTime>4:00pm</LastTradeTime> <Change>-0.48</Change> <Open>41.35</Open> <DaysHigh>42.35</DaysHigh> <DaysLow>39.60</DaysLow> <Volume>14129531</Volume> </quote> Why do I have this kind of problem? Thank you so much for your support! (P.S. I've tested it on Yahoo YQL console)

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  • date comparisons in Rails

    - by aressidi
    Hi there, I'm having trouble with a date comparison in a named scope. I'm trying to determine if an event is current based on its start and end date. Here's the named scope I'm using which kind of works, though not for events that have the same start and end date. named_scope :date_current, :conditions => ["Date(start_date) <= ? AND Date(end_date) >= ?", Time.now, Time.now] This returns the following record, though it should return two records, not one... >> Event.date_current => [#<Event id: 2161, start_date: "2010-02-15 00:00:00", end_date: "2010-02-21 00:00:00", ...] What it's not returning is this as well >> Event.find(:last) => #<Event id: 2671, start_date: "2010-02-16 00:00:00", end_date: "2010-02-16 00:00:00", ...> The server time seems to be in UTC and I presume that the entries are being stored in the DB in UTC. Any ideas as to what I'm doing wrong or what to try? Thanks!

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  • jQuery custom validation for a selected radio selection

    - by Kaushik Gopal
    Hey peeps, This is my requirement: I have a bunch of radio box selections (types of workflows). If one of the radios are selected(i.e one particular type of workflow selected), I want to run a custom validation on that. This is what i tried, but it's not behaving well. Any help? jQuery part: $(document).ready(function() { // this part is to expand the child radio selection if particular parent workflow selected $("#concernedDirectorChoice").hide(); $("input[name^=workflowChoice]").change( function (){ if($(this).attr("class")=='chooseDir'){ $("#concernedDirectorChoice").show(); }else{ $("#concernedDirectorChoice").hide(); } }); // FORM VALIDATION $.validator.addMethod("dirRequired", function(value, element) { return this.optional(element) || ($("input[name^=rdDir:checked]").length); }, "That particular workflow requires a Director to be chosen. Please select Director"); $("#contExpInitiateForm").validate({ debug:true ,rules:{ RenewalNo: {required: true, number: true}, chooseDir: {dirRequired: true}, workflowChoice: {required: true} } ,errorPlacement: function(error, element) { $('.errorMessageBox').text(error.html()); } }); }); HTML form part: <!-- Pick type of workflow --> <table class="hr-table" > <tr> <td class="hr-table-label " colspan=2 >Pick Workflow Type</td> </tr> <tr> <td> <input type="radio" name="workflowChoice" value="1"> </input> </td> <td> Workflow 1 </td> </tr> <tr> <td> <input type="radio" name="workflowChoice" value="2" class="chooseDir"> </input> </td> <td> Workflow 2 (Dir selection required) </td> </tr> <tr> <td> <input type="radio" name="workflowChoice" value="3"> </input> </td> <td> Workflow 3 </td> </tr> </table> <!-- Pick Director for Workflow type 2 --> <table id="concernedDirectorChoice" name="concernedDirectorChoice" > <tr><td class="hr-table-label" colspan=2 > Choose Concerned Director</td></tr> <tr> <td><input type="radio" value='Dir1' name="rdDir" /></td> <td>Director 1</td> </tr> <tr> <td><input type="radio" value='Dir2' name="rdDir" /></td> <td>Director 2</td> </tr> <tr> <td><input type="radio" value='Dir3' name="rdDir" /></td> <td>Director 3</td> </tr> </table>

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  • Does pressing Back always cause Activity to finish()?

    - by stormin986
    I've heard that pressing the back button will essentially cause the current Activity to finish(). Is this always the case? Seems like it would be with the way it pops the Activity off the stack. The one situation I'm not so sure about is when the root Activity in a Task has back pressed. I'm currently experiencing a very weird effect, described as follows: On loading my application, the first Activity is for initialization, and once it finishes, it calls my main Activity (a TabActivity). This first init activity has android:noHistory="true" set in the Manifest so pressing Back from my main Activity won't go back to that. It goes to the Launcher. When I click on my App in the Launcher a second time, the initialization activity loads again, and loads the main Activity when done. Almost immediately after, it loads a second instance of my main Activity. But ONLY after the Application has already been run once, and was exited by pressing BACK from the main Activity. It does it every subsequent time until I force quit the app or load a new version from the IDE. Based on this, I am suspecting some kind of Activity instance is lying around and being reused, since it only happens on the second+ time I run the application (and exit with BACK -- using HOME just returns to the last state of the app, no big deal). Anyone have any thoughts??

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  • Can't get RDFlib to work on windows

    - by john
    I have installed RDFlib 3.0 and everything that is needed, but when I run the following code I get an error. The code below is from: http://code.google.com/p/rdflib/wiki/IntroSparql. I have tried for hours to fix this but with no success. Can please someone help? import rdflib rdflib.plugin.register('sparql', rdflib.query.Processor, 'rdfextras.sparql.processor', 'Processor') rdflib.plugin.register('sparql', rdflib.query.Result, 'rdfextras.sparql.query', 'SPARQLQueryResult') from rdflib import ConjunctiveGraph g = ConjunctiveGraph() g.parse("http://bigasterisk.com/foaf.rdf") g.parse("http://www.w3.org/People/Berners-Lee/card.rdf") from rdflib import Namespace FOAF = Namespace("http://xmlns.com/foaf/0.1/") g.parse("http://danbri.livejournal.com/data/foaf") [g.add((s, FOAF['name'], n)) for s,_,n in g.triples((None, FOAF['member_name'], None))] for row in g.query( """SELECT ?aname ?bname WHERE { ?a foaf:knows ?b . ?a foaf:name ?aname . ?b foaf:name ?bname . }""", initNs=dict(foaf=Namespace("http://xmlns.com/foaf/0.1/"))): print "%s knows %s" % row The error I get is: Traceback (most recent call last): File "...", line 18 in <module> initNs=dict(foaf=Namespace("http://xmlns.com/foaf/0.1/"))): TypeError: query() got an unexpected keyword argument 'initNS'

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  • twython search api rate limit: Header information will not be updated

    - by user2715478
    I want to handle the Search-API rate limit of 180 requests / 15 minutes. The first solution I came up with was to check the remaining requests in the header and wait 900 seconds. See the following snippet: results = search_interface.cursor(search_interface.search, q=k, lang=lang, result_type=result_mode) while True: try: tweet = next(results) if limit_reached(search_interface): sleep(900) self.writer(tweet) def limit_reached(search_interface): remaining_rate = int(search_interface.get_lastfunction_header('X-Rate-Limit-Remaining')) return remaining_rate <= 2 But it seems, that the header information are not reseted to 180 after it reached the two remaining requests. The second solution I came up with was to handle the twython exception for rate limitation and wait the remaining amount of time: results = search_interface.cursor(search_interface.search, q=k, lang=lang, result_type=result_mode) while True: try: tweet = next(results) self.writer(tweet) except TwythonError as inst: logger.error(inst.msg) wait_for_reset(search_interface) continue except StopIteration: break def wait_for_reset(search_interface): reset_timestamp = int(search_interface.get_lastfunction_header('X-Rate-Limit-Reset')) now_timestamp = datetime.now().timestamp() seconds_offset = 10 t = reset_timestamp - now_timestamp + seconds_offset logger.info('Waiting {0} seconds for Twitter rate limit reset.'.format(t)) sleep(t) But with this solution I receive this message INFO: Resetting dropped connection: api.twitter.com" and the loop will not continue with the last element of the generator. Have somebody faced the same problems? Regards.

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  • DataGrid calculate difference between values in two databound cells

    - by justMe
    Hello! In my small application I have a DataGrid (see screenshot) that's bound to a list of Measurement objects. A Measurement is just a data container with two properties: Date and CounterGas (float). Each Measurement object represents my gas consumption at a specific date. The list of measurements is bound to the DataGrid as follows: <DataGrid ItemsSource="{Binding Path=Measurements}" AutoGenerateColumns="False"> <DataGrid.Columns> <DataGridTextColumn Header="Date" Binding="{Binding Path=Date, StringFormat={}{0:dd.MM.yyyy}}" /> <DataGridTextColumn Header="Counter Gas" Binding="{Binding Path=ValueGas, StringFormat={}{0:F3}}" /> </DataGrid.Columns> </DataGrid> Well, and now my question :) I'd like to have another column right next to the column "Counter Gas" which shows the difference between the actual counter value and the last counter value. E.g. this additional column should calculate the difference between the value of of Feb. 13th and Feb. 6th = 199.789 - 187.115 = 15.674 What is the best way to achieve this? I'd like to avoid any calculation in the Measurement class which should just hold the data. I'd rather more like the DataGrid to handle the calculation. So is there a way to add another column that just calculates the difference between to values? Maybe using some kind of converter and extreme binding? ;D P.S.: Maybe someone with a better reputation could embed the screenshot. Thanks :)

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  • ByteFlow installation Error on Windows

    - by Patrick
    Hi Folks, When I try to install ByteFlow on my Windows development machine, I got the following MySQL error, and I don't know what to do, please give me some suggestion. Thank you so much!!! E:\byteflow-5b6d964917b5>manage.py syncdb !!! Read about DEBUG in settings_local.py and then remove me !!! !!! Read about DEBUG in settings_local.py and then remove me !!! J:\Program Files\Python26\lib\site-packages\MySQLdb\converters.py:37: DeprecationWarning: the sets module is deprecated from sets import BaseSet, Set Creating table auth_permission Creating table auth_group Creating table auth_user Creating table auth_message Creating table django_content_type Creating table django_session Creating table django_site Creating table django_admin_log Creating table django_flatpage Creating table actionrecord Creating table blog_post Traceback (most recent call last): File "E:\byteflow-5b6d964917b5\manage.py", line 11, in <module> execute_manager(settings) File "J:\Program Files\Python26\lib\site-packages\django\core\management\__init__.py", line 362, in execute_manager utility.execute() File "J:\Program Files\Python26\lib\site-packages\django\core\management\__init__.py", line 303, in execute self.fetch_command(subcommand).run_from_argv(self.argv) File "J:\Program Files\Python26\lib\site-packages\django\core\management\base.py", line 195, in run_from_argv self.execute(*args, **options.__dict__) File "J:\Program Files\Python26\lib\site-packages\django\core\management\base.py", line 222, in execute output = self.handle(*args, **options) File "J:\Program Files\Python26\lib\site-packages\django\core\management\base.py", line 351, in handle return self.handle_noargs(**options) File "J:\Program Files\Python26\lib\site-packages\django\core\management\commands\syncdb.py", line 78, in handle_noargs cursor.execute(statement) File "J:\Program Files\Python26\lib\site-packages\django\db\backends\util.py", line 19, in execute return self.cursor.execute(sql, params) File "J:\Program Files\Python26\lib\site-packages\django\db\backends\mysql\base.py", line 84, in execute return self.cursor.execute(query, args) File "J:\Program Files\Python26\lib\site-packages\MySQLdb\cursors.py", line 166, in execute self.errorhandler(self, exc, value) File "J:\Program Files\Python26\lib\site-packages\MySQLdb\connections.py", line 35, in defaulterrorhandler raise errorclass, errorvalue _mysql_exceptions.OperationalError: (1071, 'Specified key was too long; max key length is 767 bytes')

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  • How to Force an Exception from a Task to be Observed in a Continuation Task?

    - by Richard
    I have a task to perform an HttpWebRequest using Task<WebResponse>.Factory.FromAsync(req.BeginGetRespone, req.EndGetResponse) which can obviously fail with a WebException. To the caller I want to return a Task<HttpResult> where HttpResult is a helper type to encapsulate the response (or not). In this case a 4xx or 5xx response is not an exception. Therefore I've attached two continuations to the request task. One with TaskContinuationOptions OnlyOnRanToCompletion and the other with OnlyOnOnFaulted. And then wrapped the whole thing in a Task<HttpResult> to pick up the one result whichever continuation completes. Each of the three child tasks (request plus two continuations) is created with the AttachedToParent option. But when the caller waits on the returned outer task, an AggregateException is thrown is the request failed. I want to, in the on faulted continuation, observe the WebException so the client code can just look at the result. Adding a Wait in the on fault continuation throws, but a try-catch around this doesn't help. Nor does looking at the Exception property (as section "Observing Exceptions By Using the Task.Exception Property" hints here). I could install a UnobservedTaskException event handler to filter, but as the event offers no direct link to the faulted task this will likely interact outside this part of the application and is a case of a sledgehammer to crack a nut. Given an instance of a faulted Task<T> is there any means of flagging it as "fault handled"? Simplified code: public static Task<HttpResult> Start(Uri url) { var webReq = BuildHttpWebRequest(url); var result = new HttpResult(); var taskOuter = Task<HttpResult>.Factory.StartNew(() => { var tRequest = Task<WebResponse>.Factory.FromAsync( webReq.BeginGetResponse, webReq.EndGetResponse, null, TaskCreationOptions.AttachedToParent); var tError = tRequest.ContinueWith<HttpResult>( t => HandleWebRequestError(t, result), TaskContinuationOptions.AttachedToParent |TaskContinuationOptions.OnlyOnFaulted); var tSuccess = tRequest.ContinueWith<HttpResult>( t => HandleWebRequestSuccess(t, result), TaskContinuationOptions.AttachedToParent |TaskContinuationOptions.OnlyOnRanToCompletion); return result; }); return taskOuter; } with: private static HttpDownloaderResult HandleWebRequestError( Task<WebResponse> respTask, HttpResult result) { Debug.Assert(respTask.Status == TaskStatus.Faulted); Debug.Assert(respTask.Exception.InnerException is WebException); // Try and observe the fault: Doesn't help. try { respTask.Wait(); } catch (AggregateException e) { Log("HandleWebRequestError: waiting on antecedent task threw inner: " + e.InnerException.Message); } // ... populate result with details of the failure for the client ... return result; } (HandleWebRequestSuccess will eventually spin off further tasks to get the content of the response...) The client should be able to wait on the task and then look at its result, without it throwing due to a fault that is expected and already handled.

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  • Is nested synchronized block necessary?

    - by Dan
    I am writing a multithreaded program and I have a method that has a nested synchronized blocks and I was wondering if I need the inner sync or if just the outer sync is good enough. public class Tester { private BlockingQueue<Ticket> q = new LinkedBlockingQueue<>(); private ArrayList<Long> list = new ArrayList<>(); public void acceptTicket(Ticket p) { try { synchronized (q) { q.put(p); synchronized (list) { if (list.size() < 5) { list.add(p.getSize()); } else { list.remove(0); list.add(p.getSize()); } } } } catch (InterruptedException ex) { Logger.getLogger(Consumer.class.getName()).log(Level.SEVERE, null, ex); } } } EDIT: This isn't a complete class as I am still working on it. But essentially I am trying to emulate a ticket machine. The ticket machine maintains a list of tickets in the BlockingQueue q. Whenever a client adds a ticket to the machine, the machine also keeps track of the price of the last 5 tickets (ArrayList list)

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  • Execute Stored Procedure from Classic ASP

    - by Jaco Pretorius
    For some fantastic reason I find myself debugging a problem in a Classic ASP page (at least 10 years of my life lost in the last 2 days). I'm trying to execute a stored procedure which contains some OUT parameters. The problem is that one of the OUT parameters is not being populated when the stored procedure returns. I can execute the stored proc from SQL management studio (this is 2008) and all the values are being set and returned exactly as expected. declare @inVar1 varchar(255) declare @inVar2 varchar(255) declare @outVar1 varchar(255) declare @outVar2 varchar(255) SET @inVar2 = 'someValue' exec theStoredProc @inVar1 , @inVar2 , @outVar1 OUT, @outVar2 OUT print '@outVar1=' + @outVar1 print '@outVar2=' + @outVar2 Works great. Fantastic. Perfect. The exact values that I'm expecting are being returned and printed out. Right, since I'm trying to debug a Classic ASP page I copied the code into a VBScript file to try and narrow down the problem. Here is what I came up with: Set Conn = CreateObject("ADODB.Connection") Conn.Open "xxx" Set objCommandSec = CreateObject("ADODB.Command") objCommandSec.ActiveConnection = Conn objCommandSec.CommandType = 4 objCommandSec.CommandText = "theStoredProc " objCommandSec.Parameters.Refresh objCommandSec.Parameters(2) = "someValue" objCommandSec.Execute MsgBox(objCommandSec.Parameters(3)) Doesn't work. Not even a little bit. (Another ten years of my life down the drain) The third parameter is simply NULL - which is what I'm experiencing in the Classic ASP page as well. Could someone shed some light on this? Am I completely daft for thinking that the classic ASP code would be the same as the VBScript code? I think it's using the same scripting engine and syntax so I should be ok, but I'm not 100% sure. The result I'm seeing from my VBScript is the same as I'm seeing in ASP.

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  • CSS column height different on Opera/IE to FF

    - by Infiniti Fizz
    Hi all, Thanks to everyone who helped with my last question but I've got a new browser-independent problem: For some reason, the image navigator (not yet functioning) on a website I'm working on is currently not displaying in the correct place on Firefox. It appears in the right place in IE8 and Opera but Firefox seems to have a problem with it. As can be seen in the below image, the imageContainer div (the image and the left/right arrows) appears on top of the footer, this is how it should look i.e. how it looks in IE8 and Opera. But in the image below, the imageContainer div is cutting into the footer div for some reason, and I don't know why. imageContainer has a margin-top: 110px; to get it in the right place at the bottom of its column. There are 2 columns, the left housing the paragraphs and imageContainer and the right housing the Calendar and contact details. The footer div also has clear: both; Also, it's not just the image that is falling into the footer, it's the arrows as well only they are the same colour as the footer so this isn't immediately apparent. Any ideas why it isn't displaying correctly? Is there a better way of aligning the imageContainer to the bottom of it's column (to keep the box shape of the website) other than using the margin-top to position it? Thanks in advance, infinitifizz

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  • How to do parrallel processing in Unix Shell script?

    - by Bikram Agarwal
    I have a shell script that transfers a build.xml file to a remote unix machine (devrsp02) and executes the ANT task wldeploy on that machine (devrsp02). Now, this wldeploy task takes around 15 minutes to complete and while this is running, the last line at the unix console is - "task {some digit} initialized". Once this task is complete, we get a "task Completed" msg and the next task in the script is executed only after that. But sometimes, there might be a problem with the weblogic domain and the deployment might be failing internally, with no effect on the status of the wldeploy task. The unix console will still be stuck at "task {some digit} initialized". The error of the deployment will be getting logged in a file called output.a So, what I want now is - Start a time counter before running wldeploy. If the wldeploy runs for more than 15 minutes, the following command should be run - tail -f output.a ## without terminating the wldeploy or cat output.a ## after terminating the wldeploy forcefully Point to be noted here is - I can't run the wldeploy task in background, as in that case the user won't get to know when the task is complete, which is crucial for this script. Could you please suggest anything to achieve this?

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  • What can I do about ambigous wildcard patterns in Struts?

    - by Hanno Fietz
    I have a problem finding the right wildcard pattern to extract parts of my URL into action parameters in Struts. This is how I set up the action. The intent of the pattern is to capture the last two path elements and then everything that might precede them. <action name="**/*/*" class="com.example.ObjectAction"> <param name="filter">{1}</param> <param name="type">{2}</param> <param name="id">{3}</param> </action> Calling it with the URL channels/123/transmissions/456 I get the following result (the action just sets the input parameters on a POJO and returns that as XML): <result> <filter>channels/123/transmissions</filter> <id/> <type>456</type> </result> It should be: <result> <filter>channels/123</filter> <id>456</id> <type>transmissions</type> </result> Now, because ** matches all characters including the slash, I guess my pattern allows more than one way to match the URL, and Struts happens to pick one that leaves the id empty. Is the behaviour for multiple possible matches defined somewhere? Can I make the pattern less ambigous? Are there alternative ways of doing this? I'm running Struts 2.0.8. Upgrading to 2.1.9 would give me regex matching, but I got into trouble with Struts' dependencies and my OSGi environment when I went past 2.0.8, so I'd like to stick to that version for now.

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  • I seek a PDF paginator

    - by Cameron Laird
    More precisely, I need software that will allow me to consume existing PDF instances, decorate them with page numbers, or page-number-like writing, then write them back to the filesystem. I'll happily pay for an application, or program it myself. I almost certainly require the software run under Linux (Ubuntu, more specifically). iText comes close. iText certainly can read existing PDF instances. While iText is, for this purpose, only a library, and requires me to program a tiny amount to specify where on the page the numbers should appear, I'm happy to do that. I hesitate with iText only because the latest iText license is a headache at certain government agencies (in practice, I'd probably request and pay for a special license), and because, over the last few years, I've observed cases where iText doesn't appear to keep up with the standard, that is, it has more troubles than I expect reading PDFs observed "in the wild". Similarly, every other possibility I know has at least one difficulty: ReportLab would likely require a disproportionate licensing fee for the small value it provides in this situation, and so on. This application requires no particular sophistication with Unicode, fonts, ... I recognize there are plenty of executables and libraries that do some or all of what I require. I welcome any tips on software that is reliable, generally current with PDF practice, flexible/programmable/configurable/..., and "automatable". In the absence of any new insight, I'll likely go with a specific open-source library I don't want to mention now for which I've already contracted enhancements, or perhaps revisit iText.

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  • How can I print text fields at the right coordinates?

    - by Milad
    I don't have any background in programming and this is my first shot. I wrote a Delphi program that is supposed to print on a result sheet. I work in an institute and we have to establish hundreds of result sheets every 2 months. It's really difficult to do that and different handwriting is also an important issue. I have this code: if PrintDialog.Execute() then begin with MyPrinter do begin MyPrinter.BeginDoc();//Start Printing //Prints First Name MyPrinter.Canvas.TextOut(FirstNameX,FirstNameY,EditFirstName.Text); //Prints Last Name MyPrinter.Canvas.TextOut(LastNameX,LastNameY,EditLastName.Text); //Prints Level MyPrinter.Canvas.TextOut(LevelX,LevelY,EditLevel.Text); //Prints Date MyPrinter.Canvas.TextOut(DateX,DateY,MEditDate.Text); //Prints Student Number MyPrinter.Canvas.TextOut(StdNumX,StdNumY,EditStdnumber.Text); .... MyPrinter.EndDoc();//End Printing end; end; I can't get the right coordinates to print properly. Am I missing something? How can I set the right coordinates? You know TPrinter uses pixels to get the coordinates but papers are measured in inches or centimeters. I'm really confused. I appreciate any help.

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  • How to use the same element name in different purposes ( in XML and DTD ) ?

    - by BugKiller
    Hi, I Want to create a DTD schema for this xml document: <root> <student> <name> <firstname>S1</firstname> <lastname>S2</lastname> </name> </student> <course> <name>CS101</name> </course> </root> as you can see , the element name in the course contains plain text ,but the element name in the student is complex type ( first-name, last-name ). The following is the DTD: <!ELEMENT root (course|student)*> <!ELEMENT student (name)> <!ELEMENT name (lastname|firstname)> <!ELEMENT firstname (#PCDATA)> <!ELEMENT lastname (#PCDATA)> <!ELEMENT course (name)> When I want to validate it , I get an error because the course's name has different structure then the student's name . My Question: how can I make a work-around solution for this situation without changing the name of element name using DTD not xml schema . Thanks.

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