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  • eXML-PARSER output contains unwanted hash references

    - by seaworthy
    So I wrote a parser routine to take one xml file and reparse into another one. This code I later modified to split a large xml file into many small xml files. I am having a problem with an output. Parsing works fine the only thing output also includes unwanted strings like HASH(0x19f9b58), I am not sure why and need set of friendly eyes. use Encode; use XML::Parser; my $parser = XML::Parser->new( Handlers => {Start => \&handle_elem_start, End => \&handle_elem_end,Char => \&handle_char_data,}); my $record; my $file = shift @ARGV; if( $file ) {$parser->parsefile( $file );} exit; sub handle_elem_start { my( $expat, $name, %atts ) = @_; if ($name eq 'articles'){$file="_data.xml";unlink($file);} $record .= "<"; $record .= "$name"; foreach my $key (keys %atts){$record .= " $key=\"$atts{$key}\"";} $record .= ">"; } sub handle_char_data { my( $expat, $text ) = @_; $text = decode_utf8( $text ); $record .= "$text"; } sub handle_elem_end { my( $expat, $name ) = @_; $record .= "</$name>"; if( $name eq 'article' ) { open (MYFILE, '>>'.$file); print MYFILE $record; close (MYFILE); print $record; $record = {}; } return unless( $name eq 'article' ); } Sample output: ... </article>HASH(0x19f9b40) <article doi="10.1103/PhysRevSeriesI.9.304"> <journal short="Phys. Rev. (Series I)" jcode="PRI">Physical Review (Series I)</journal> <volume>9</volume> <issue printdate="1899-11-00">5</issue> <fpage>304</fpage> <lpage>309</lpage> <seqno>1</seqno> <price></price><tocsec>Articles</tocsec> <arttype type="article"></arttype><doi>10.1103/PhysRevSeriesI.9.304</doi> <title>An Investigation of the Magnetic Qualities of Building Brick</title> <authgrp> <author><givenname>O.</givenname><middlename>A.</middlename><surname>Gage</surname></author> <author><givenname>H.</givenname><middlename>E.</middlename><surname>Lawrence</surname></author> </authgrp> <cpyrt> <cpyrtdate date="1899"></cpyrtdate><cpyrtholder>The American Physical Society</cpyrtholder> </cpyrt> </article>HASH(0x19f9b58) ... HASH strings are not wanted, please advise.

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  • Call a void* as a function without declaring a function pointer

    - by ToxIk
    I've searched but couldn't find any results (my terminology may be off) so forgive me if this has been asked before. I was wondering if there is an easy way to call a void* as a function in C without first declaring a function pointer and then assigning the function pointer the address; ie. assuming the function to be called is type void(void) void *ptr; ptr = <some address>; ((void*())ptr)(); /* call ptr as function here */ with the above code, I get error C2066: cast to function type is illegal in VC2008 If this is possible, how would the syntax differ for functions with return types and multiple parameters?

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  • array of pointers

    - by tushar
    char *a[]={"diamonds","clubs","spades","hearts"}; char **p[]={a+3,a+2,a+1,a}; char ***ptr=p; cout<<*ptr[2][2]; why does it display h and please explain how is the 2d array of ptr implementing and its elements

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  • UTF-8 to Unicode conversion

    - by sandeep
    Hi, I am having problems with converting UTF-8 to Unicode. Below is the code: int charset_convert( char * string, char * to_string,char* charset_from, char* charset_to) { char *from_buf, *to_buf, *pointer; size_t inbytesleft, outbytesleft, ret; size_t TotalLen; iconv_t cd; if (!charset_from || !charset_to || !string) /* sanity check */ return -1; if (strlen(string) < 1) return 0; /* we are done, nothing to convert */ cd = iconv_open(charset_to, charset_from); /* Did I succeed in getting a conversion descriptor ? */ if (cd == (iconv_t)(-1)) { /* I guess not */ printf("Failed to convert string from %s to %s ", charset_from, charset_to); return -1; } from_buf = string; inbytesleft = strlen(string); /* allocate max sized buffer, assuming target encoding may be 4 byte unicode */ outbytesleft = inbytesleft *4 ; pointer = to_buf = (char *)malloc(outbytesleft); memset(to_buf,0,outbytesleft); memset(pointer,0,outbytesleft); ret = iconv(cd, &from_buf, &inbytesleft, &pointer, &outbytesleft);ing memcpy(to_string,to_buf,(pointer-to_buf); } main(): int main() { char UTF []= {'A', 'B'}; char Unicode[1024]= {0}; char* ptr; int x=0; iconv_t cd; charset_convert(UTF,Unicode,"UTF-8","UNICODE"); ptr = Unicode; while(*ptr != '\0') { printf("Unicode %x \n",*ptr); ptr++; } return 0; } It should give A and B but i am getting: ffffffff fffffffe 41 Thanks, Sandeep

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  • When does printf("%s", char*) stop printing?

    - by remagen
    In my class we are writing our own copy of C's malloc() function. To test my code (which can currently allocate space fine) I was using: char* ptr = my_malloc(6*sizeof(char)); memcpy(ptr, "Hello\n", 6*sizeof(char)); printf("%s", ptr); The output would typically be this: Hello Unprintable character Some debugging figured that my code wasn't causing this per say, as ptr's memory is as follows: [24 bytes of meta info][Number of requested bytes][Padding] So I figured that printf was reaching into the padding, which is just garbage. So I ran a test of: printf("%s", "test\nd"); and got: test d Which makes me wonder, when DOES printf("%s", char*) stop printing chars?

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  • Accessing structure elements using pointers

    - by Arun Nadesh
    Hi Everybody, Greetings! I got surprised when the following program did not crash. typedef struct _x{ int a; char b; int c; }x; main() { x *ptr=0; char *d=&ptr->b; } As per my understanding the -> operator has higher precedence over & operator. So I expected the program to crash at the below statement when we try to dereference the NULL pointer tr. char *d=&ptr->b; But the statement &ptr->b evaluates to a valid address. Could somebody please explain where I'm wrong? Thanks & Regards, Arun

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  • Design Pattern for Complex Data Modeling

    - by Aaron Hayman
    I'm developing a program that has a SQL database as a backing store. As a very broad description, the program itself allows a user to generate records in any number of user-defined tables and make connections between them. As for specs: Any record generated must be able to be connected to any other record in any other user table (excluding itself...the record, not the table). These "connections" are directional, and the list of connections a record has is user ordered. Moreover, a record must "know" of connections made from it to others as well as connections made to it from others. The connections are kind of the point of this program, so there is a strong possibility that the number of connections made is very high, especially if the user is using the software as intended. A record's field can also include aggregate information from it's connections (like obtaining average, sum, etc) that must be updated on change from another record it's connected to. To conserve memory, only relevant information must be loaded at any one time (can't load the entire database in memory at load and go from there). I cannot assume the backing store is local. Right now it is, but eventually this program will include syncing to a remote db. Neither the user tables, connections or records are known at design time as they are user generated. I've spent a lot of time trying to figure out how to design the backing store and the object model to best fit these specs. In my first design attempt on this, I had one object managing all a table's records and connections. I attempted this first because it kept the memory footprint smaller (records and connections were simple dicts), but maintaining aggregate and link information between tables became....onerous (ie...a huge spaghettified mess). Tracing dependencies using this method almost became impossible. Instead, I've settled on a distributed graph model where each record and connection is 'aware' of what's around it by managing it own data and connections to other records. Doing this increases my memory footprint but also let me create a faulting system so connections/records aren't loaded into memory until they're needed. It's also much easier to code: trace dependencies, eliminate cycling recursive updates, etc. My biggest problem is storing/loading the connections. I'm not happy with any of my current solutions/ideas so I wanted to ask and see if anybody else has any ideas of how this should be structured. Connections are fairly simple. They contain: fromRecordID, fromTableID, fromRecordOrder, toRecordID, toTableID, toRecordOrder. Here's what I've come up with so far: Store all the connections in one big table. If I do this, either I load all connections at once (one big db call) or make a call every time a user table is loaded. The big issue here: the size of the connections table has the potential to be huge, and I'm afraid it would slow things down. Store in separate tables all the outgoing connections for each user table. This is probably the worst idea I've had. Now my connections are 'spread out' over multiple tables (one for each user table), which means I have to make a separate DB called to each table (or make a huge join) just to find all the incoming connections for a particular user table. I've avoided making "one big ass table", but I'm not sure the cost is worth it. Store in separate tables all outgoing AND incoming connections for each user table (using a flag to distinguish between incoming vs outgoing). This is the idea I'm leaning towards, but it will essentially double the total DB storage for all the connections (as each connection will be stored in two tables). It also means I have to make sure connection information is kept in sync in both places. This is obviously not ideal but it does mean that when I load a user table, I only need to load one 'connection' table and have all the information I need. This also presents a separate problem, that of connection object creation. Since each user table has a list of all connections, there are two opportunities for a connection object to be made. However, connections objects (designed to facilitate communication between records) should only be created once. This means I'll have to devise a common caching/factory object to make sure only one connection object is made per connection. Does anybody have any ideas of a better way to do this? Once I've committed to a particular design pattern I'm pretty much stuck with it, so I want to make sure I've come up with the best one possible.

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  • SQL Server Table Polling by Multiple Subscribers

    - by Daniel Hester
    Background Designing Stored Procedures that are safe for multiple subscribers (to call simultaneously) can be challenging.  For example let’s say that you want multiple worker processes to poll a shared work queue that’s encapsulated as a SQL Table. This is a common scenario and through experience you’ll find that you want to use Table Hints to prevent unwanted locking when performing simultaneous queries on the same table. There are three table hints to consider: NOLOCK, READPAST and UPDLOCK. Both NOLOCK and READPAST table hints allow you to SELECT from a table without placing a LOCK on that table. However, SELECTs with the READPAST hint will ignore any records that are locked due to being updated/inserted (or otherwise “dirty”), whereas a SELECT with NOLOCK ignores all locks including dirty reads. For the initial update of the flag (that marks the record as available for subscription) I don’t use the NOLOCK Table Hint because I want to be sensitive to the “active” records in the table and I want to exclude them.  I use an Update Lock (UPDLOCK) in conjunction with a WHERE clause that uses a sub-select with a READPAST Table Hint in order to explicitly lock the records I’m updating (UPDLOCK) but not place a lock on the table when selecting the records that I’m going to update (READPAST). UPDATES should be allowed to lock the rows affected because we’re probably changing a flag on a record so that it is not included in a SELECT from another subscriber. On the UPDATE statement we should explicitly use the UPDLOCK to guard against lock escalation. A SELECT to check for the next record(s) to process can result in a shared read lock being held by more than one subscriber polling the shared work queue (SQL table). It is expected that more than one worker process (or server) might try to process the same new record(s) at the same time. When each process then tries to obtain the update lock, none of them can because another process has a shared read lock in place. Thus without the UPDLOCK hint the result would be a lock escalation deadlock; however with the UPDLOCK hint this condition is mitigated against. Note that using the READPAST table hint requires that you also set the ISOLATION LEVEL of the transaction to be READ COMMITTED (rather than the default of SERIALIZABLE). Guidance In the Stored Procedure that returns records to the multiple subscribers: Perform the UPDATE first. Change the flag that makes the record available to subscribers.  Additionally, you may want to update a LastUpdated datetime field in order to be able to check for records that “got stuck” in an intermediate state or for other auditing purposes. In the UPDATE statement use the (UPDLOCK) Table Hint on the UPDATE statement to prevent lock escalation. In the UPDATE statement also use a WHERE Clause that uses a sub-select with a (READPAST) Table Hint to select the records that you’re going to update. In the UPDATE statement use the OUTPUT clause in conjunction with a Temporary Table to isolate the record(s) that you’ve just updated and intend to return to the subscriber. This is the fastest way to update the record(s) and to get the records’ identifiers within the same operation. Finally do a set-based SELECT on the main Table (using the Temporary Table to identify the records in the set) with either a READPAST or NOLOCK table hint.  Use NOLOCK if there are other processes (besides the multiple subscribers) that might be changing the data that you want to return to the multiple subscribers; or use READPAST if you're sure there are no other processes (besides the multiple subscribers) that might be updating column data in the table for other purposes (e.g. changes to a person’s last name).  NOLOCK is generally the better fit in this part of the scenario. See the following as an example: CREATE PROCEDURE [dbo].[usp_NewCustomersSelect] AS BEGIN -- OVERRIDE THE DEFAULT ISOLATION LEVEL SET TRANSACTION ISOLATION LEVEL READ COMMITTED -- SET NOCOUNT ON SET NOCOUNT ON -- DECLARE TEMP TABLE -- Note that this example uses CustomerId as an identifier; -- you could just use the Identity column Id if that’s all you need. DECLARE @CustomersTempTable TABLE ( CustomerId NVARCHAR(255) ) -- PERFORM UPDATE FIRST -- [Customers] is the name of the table -- [Id] is the Identity Column on the table -- [CustomerId] is the business document key used to identify the -- record globally, i.e. in other systems or across SQL tables -- [Status] is INT or BIT field (if the status is a binary state) -- [LastUpdated] is a datetime field used to record the time of the -- last update UPDATE [Customers] WITH (UPDLOCK) SET [Status] = 1, [LastUpdated] = GETDATE() OUTPUT [INSERTED].[CustomerId] INTO @CustomersTempTable WHERE ([Id] = (SELECT TOP 100 [Id] FROM [Customers] WITH (READPAST) WHERE ([Status] = 0) ORDER BY [Id] ASC)) -- PERFORM SELECT FROM ENTITY TABLE SELECT [C].[CustomerId], [C].[FirstName], [C].[LastName], [C].[Address1], [C].[Address2], [C].[City], [C].[State], [C].[Zip], [C].[ShippingMethod], [C].[Id] FROM [Customers] AS [C] WITH (NOLOCK), @CustomersTempTable AS [TEMP] WHERE ([C].[CustomerId] = [TEMP].[CustomerId]) END In a system that has been designed to have multiple status values for records that need to be processed in the Work Queue it is necessary to have a “Watch Dog” process by which “stale” records in intermediate states (such as “In Progress”) are detected, i.e. a [Status] of 0 = New or Unprocessed; a [Status] of 1 = In Progress; a [Status] of 2 = Processed; etc.. Thus, if you have a business rule that states that the application should only process new records if all of the old records have been processed successfully (or marked as an error), then it will be necessary to build a monitoring process to detect stalled or stale records in the Work Queue, hence the use of the LastUpdated column in the example above. The Status field along with the LastUpdated field can be used as the criteria to detect stalled / stale records. It is possible to put this watchdog logic into the stored procedure above, but I would recommend making it a separate monitoring function. In writing the stored procedure that checks for stale records I would recommend using the same kind of lock semantics as suggested above. The example below looks for records that have been in the “In Progress” state ([Status] = 1) for greater than 60 seconds: CREATE PROCEDURE [dbo].[usp_NewCustomersWatchDog] AS BEGIN -- TO OVERRIDE THE DEFAULT ISOLATION LEVEL SET TRANSACTION ISOLATION LEVEL READ COMMITTED -- SET NOCOUNT ON SET NOCOUNT ON DECLARE @MaxWait int; SET @MaxWait = 60 IF EXISTS (SELECT 1 FROM [dbo].[Customers] WITH (READPAST) WHERE ([Status] = 1) AND (DATEDIFF(s, [LastUpdated], GETDATE()) > @MaxWait)) BEGIN SELECT 1 AS [IsWatchDogError] END ELSE BEGIN SELECT 0 AS [IsWatchDogError] END END Downloads The zip file below contains two SQL scripts: one to create a sample database with the above stored procedures and one to populate the sample database with 10,000 sample records.  I am very grateful to Red-Gate software for their excellent SQL Data Generator tool which enabled me to create these sample records in no time at all. References http://msdn.microsoft.com/en-us/library/ms187373.aspx http://www.techrepublic.com/article/using-nolock-and-readpast-table-hints-in-sql-server/6185492 http://geekswithblogs.net/gwiele/archive/2004/11/25/15974.aspx http://grounding.co.za/blogs/romiko/archive/2009/03/09/biztalk-sql-receive-location-deadlocks-dirty-reads-and-isolation-levels.aspx

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  • Java Desktop Application For Network users

    - by Motasem Abu Aker
    I'm developing a desktop application using Java. My application will run in a network environment where multiple users will access the same database through the application. There will be basic CRUD opreations (Insert, Update, Delete, & select), which means there will be chances of deadlock, or two users trying to update the same record at same time. I'm using the following Java Swing for Clients (MVC). MySQL Server for database (InnODB). Java Web start. Now, MySQL is centralized on the network, and all of the clients connect to it. The Application for ERP Purpose. I searched the internet to find a very good solution to ensure data integrity & to make sure that when updating one record from one client, other clients are aware of it. I read about Socket-server-client & RESTful web services. I don't want to go web application & don't want to use any extra libraries. So how can I handle this scenario: If User A updates a record: Is there a way to update User B's screen with the new value? If user A starts updating a record, how can I prevent other users from attempting to update the same record?

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  • How to display a person record just after saving his data to iPhone Address Book?

    - by camelCase
    this is my code and it works flawless, where my_value is a string with separator ','. everythign works fin but i'd like to display the person record from the address book after i saved it, so in the function if(isSaved) { // **** code here *** } here the complete function - (void) addToAgenda: (NSString*) my_value{ //NSArray *strings = [my_value componentsSeparatedByString: @","]; NSArray *dati=[[NSArray alloc] initWithArray:[my_value componentsSeparatedByString:@","]]; NSString *userwebsite = [dati objectAtIndex:0]; NSString *fname = [dati objectAtIndex:1]; NSString *lname = [dati objectAtIndex:2]; NSString *useremail = [dati objectAtIndex:3];; NSString *usermobile = [dati objectAtIndex:4]; NSString *usercompany = @"xxx"; ABRecordRef aRecord = ABPersonCreate(); CFErrorRef anError = NULL; // fisrst name ABRecordSetValue(aRecord, kABPersonFirstNameProperty, fname, &anError); // last name ABRecordSetValue(aRecord, kABPersonLastNameProperty, lname, &anError); // Phone Number. ABMutableMultiValueRef multi = ABMultiValueCreateMutable(kABMultiStringPropertyType); ABMultiValueAddValueAndLabel(multi, (CFStringRef)usermobile, kABWorkLabel, NULL); ABRecordSetValue(aRecord, kABPersonPhoneProperty, multi, &anError); CFRelease(multi); // Company ABRecordSetValue(aRecord, kABPersonDepartmentProperty, usercompany, &anError); // email NSLog(@"%@", useremail); ABMutableMultiValueRef multiemail = ABMultiValueCreateMutable(kABMultiStringPropertyType); ABMultiValueAddValueAndLabel(multiemail, (CFStringRef)useremail, kABWorkLabel, NULL); ABRecordSetValue(aRecord, kABPersonEmailProperty, multiemail, &anError); CFRelease(multiemail); // website NSLog(@"%@", userwebsite); ABMutableMultiValueRef multiweb = ABMultiValueCreateMutable(kABMultiStringPropertyType); ABMultiValueAddValueAndLabel(multiweb, (CFStringRef)userwebsite, kABWorkLabel, NULL); ABRecordSetValue(aRecord, kABPersonURLProperty, multiweb, &anError); CFRelease(multiemail); if (anError != NULL) NSLog(@"error while creating.."); CFStringRef personname, personlname, personcompind, personemail, personwebsite, personcontact; personname = ABRecordCopyValue(aRecord, kABPersonFirstNameProperty); personlname = ABRecordCopyValue(aRecord, kABPersonLastNameProperty); personcompind = ABRecordCopyValue(aRecord, kABPersonDepartmentProperty); personemail = ABRecordCopyValue(aRecord, kABPersonEmailProperty); personwebsite = ABRecordCopyValue(aRecord, kABPersonURLProperty); personcontact = ABRecordCopyValue(aRecord, kABPersonPhoneProperty); ABAddressBookRef addressBook; CFErrorRef error = NULL; addressBook = ABAddressBookCreate(); BOOL isAdded = ABAddressBookAddRecord (addressBook, aRecord, &error); if(isAdded){ NSLog(@"added.."); } if (error != NULL) { NSLog(@"ABAddressBookAddRecord %@", error); } error = NULL; BOOL isSaved = ABAddressBookSave (addressBook, &error); if(isSaved) { // **** code here *** } if (error != NULL) { NSLog(@"ABAddressBookSave %@", error); UIAlertView *alertOnChoose = [[UIAlertView alloc] initWithTitle:@"Unable to save this time" message:nil delegate:self cancelButtonTitle:nil otherButtonTitles:@"Ok", nil]; [alertOnChoose show]; [alertOnChoose release]; } CFRelease(aRecord); CFRelease(personname); CFRelease(personlname); CFRelease(personcompind); CFRelease(personcontact); CFRelease(personemail); CFRelease(personwebsite); CFRelease(addressBook); }

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  • Compiled Haskell libraries with FFI imports are invalid when imported into GHCI

    - by John Millikin
    I am using GHC 6.12.1, in Ubuntu 10.04 When I try to use the FFI syntax for static storage, only modules running in interpreted mode (ie GHCI) work properly. Compiled modules have invalid pointers, and do not work. I'd like to know whether anybody can reproduce the problem, whether this an error in my code or GHC, and (if the latter) whether it's a known issue. I'm using sys_siglist because it's present in a standard library on my system, but I don't believe the actual storage used matters (I discovered this while writing a binding to libidn). If it helps, sys_siglist is defined in <signal.h> as: extern __const char *__const sys_siglist[_NSIG]; I thought this type might be the problem, so I also tried wrapping it in a plain C procedure: #include<stdio.h> const char **test_ffi_import() { printf("C think sys_siglist = %X\n", sys_siglist); return sys_siglist; } However, importing that doesn't change the result, and the printf() call prints the same pointer value as show siglist_a. My suspicion is that it's something to do with static and dynamic library loading. Update: somebody in #haskell suggested this might be 64-bit specific; if anybody tries to reproduce it, can you mention your architecture and whether it worked in a comment? Code as follows: -- A.hs {-# LANGUAGE ForeignFunctionInterface #-} module A where import Foreign import Foreign.C foreign import ccall "&sys_siglist" siglist_a :: Ptr CString -- -- B.hs {-# LANGUAGE ForeignFunctionInterface #-} module B where import Foreign import Foreign.C foreign import ccall "&sys_siglist" siglist_b :: Ptr CString -- -- Main.hs {-# LANGUAGE ForeignFunctionInterface #-} module Main where import Foreign import Foreign.C import A import B foreign import ccall "&sys_siglist" siglist_main :: Ptr CString main = do putStrLn $ "siglist_a = " ++ show siglist_a putStrLn $ "siglist_b = " ++ show siglist_b putStrLn $ "siglist_main = " ++ show siglist_main peekSiglist "a " siglist_a peekSiglist "b " siglist_b peekSiglist "main" siglist_main peekSiglist name siglist = do ptr <- peekElemOff siglist 2 str <- maybePeek peekCString ptr putStrLn $ "siglist_" ++ name ++ "[2] = " ++ show str I would expect something like this output, where all pointer values identical and valid: $ runhaskell Main.hs siglist_a = 0x00007f53a948fe00 siglist_b = 0x00007f53a948fe00 siglist_main = 0x00007f53a948fe00 siglist_a [2] = Just "Interrupt" siglist_b [2] = Just "Interrupt" siglist_main[2] = Just "Interrupt" However, if I compile A.hs (with ghc -c A.hs), then the output changes to: $ runhaskell Main.hs siglist_a = 0x0000000040378918 siglist_b = 0x00007fe7c029ce00 siglist_main = 0x00007fe7c029ce00 siglist_a [2] = Nothing siglist_b [2] = Just "Interrupt" siglist_main[2] = Just "Interrupt"

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  • Increase the size of a memory mapped file

    - by sandun dhammika
    I am maintaning a memory mapped file to store my tree like datastructure. When I'm updating the datastructure ,I got this problem. The file is limited on it's size and can't be too long or too small. I have a methods like void mapfile_insert_record(RECORD* /* record*/); void mapfile_modify_record(RECORD* /* record*/); Both operations could lead to exceed the space which is free on memory file. How do I overcome this? What strategy I should use. calculate whether it requires to exceed the file as a pre-condition on both methods. Dynamically exceed it , for a example manage a timer and constantly polling file for it's free avaliable size and then automatically extend it. Any ideas or patterns to overcome this problem?

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  • what is the best program to capture my workings as an AVI or MPEG

    - by raihanchy
    I have already used recordmydesktop, xvidcap and kazam. My sound working fine with other audio or videos. xvidcap doesn't record sound at all. I have tried many ways. If I try as: 'padsp xvidcap', it also gives error, like: /dev/dsp cannot found or missing. I have changed it to /dev/snd. Still no effect. Even I can record sound through gnome-sound-recorder - after pressing record button, I open pavucontrol. Then from Recording tab, I choose 'Monitor of Analog Stereo'. But if I run xvidcap, I don't get that option in pavucontrol. kazam works a bit slow. It records at the beginning of the captured video. But for unknown reason, it eventually the sounds just go off. Also the video is not smooth as xvidcap. Though Kazam output as H64/MP4. Record my Desktop also doesn't give sound. Can you guys please help me, either - how to get sound with xvidcap or how kazam could be record nicely. I am looking something Camtasia, as used for Windows. Thanks in advance. Raihan

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  • Explanation of various domain name records?

    - by Kumar
    At the time of hosting, normally we just change name servers in the domain control panel. It's fine if both mail and web servers are the same. When they're different, we need to change the DNS records. When I try to point my blog to my domain name, I came to know about the various types of DNS records - A Records, AAA Records, MX Records, CNAME Records, NS Records, TXT Records, SRV Records, SOA Records, etc. I searched on Google, but would like to know more about these deeply. I found this link on the Internet - http://www.directnic.com/help/faq/?question_id=103 and got some idea about the different DNS records. But I have some more questions. How do the domain name records work? Is there any difference between NS record and other records in the way they work? Where should the NS record point to when using A record, CNAME record and MX record?

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  • Why no switch on pointers?

    - by meeselet
    For instance: #include <stdio.h> void why_cant_we_switch_him(void *ptr) { switch (ptr) { case NULL: printf("NULL!\n"); break; default: printf("%p!\n", ptr); break; } } int main(void) { void *foo = "toast"; why_cant_we_switch_him(foo); return 0; } gcc test.c -o test test.c: In function 'why_cant_we_switch_him': test.c:5: error: switch quantity not an integer test.c:6: error: pointers are not permitted as case values Just curious. Is this a technical limitation? EDIT People seem to think there is only one constant pointer expression. Is that is really true, though? For instance, here is a common paradigm in Objective-C (it is really only C aside from NSString, id and nil, which are merely a pointers, so it is still relevant — I just wanted to point out that there is, in fact, a common use for it, despite this being only a technical question): #include <stdio.h> #include <Foundation/Foundation.h> static NSString * const kMyConstantObject = @"Foo"; void why_cant_we_switch_him(id ptr) { switch (ptr) { case kMyConstantObject: // (Note that we are comparing pointers, not string values.) printf("We found him!\n"); break; case nil: printf("He appears to be nil (or NULL, whichever you prefer).\n"); break; default: printf("%p!\n", ptr); break; } } int main(void) { NSString *foo = @"toast"; why_cant_we_switch_him(foo); foo = kMyConstantObject; why_cant_we_switch_him(foo); return 0; } gcc test.c -o test -framework Foundation test.c: In function 'why_cant_we_switch_him': test.c:5: error: switch quantity not an integer test.c:6: error: pointers are not permitted as case values It appears that the reason is that switch only allows integral values (as the compiler warning said). So I suppose a better question would be to ask why this is the case? (though it is probably too late now.)

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  • Why do compiled Haskell libraries see invalid static FFI storage?

    - by John Millikin
    I am using GHC 6.12.1, in Ubuntu 10.04 When I try to use the FFI syntax for static storage, only modules running in interpreted mode (ie GHCI) work properly. Compiled modules have invalid pointers, and do not work. I'd like to know whether anybody can reproduce the problem, whether this an error in my code or GHC, and (if the latter) whether it's a known issue. Given the following three modules: -- A.hs {-# LANGUAGE ForeignFunctionInterface #-} module A where import Foreign import Foreign.C foreign import ccall "&sys_siglist" siglist_a :: Ptr CString -- -- B.hs {-# LANGUAGE ForeignFunctionInterface #-} module B where import Foreign import Foreign.C foreign import ccall "&sys_siglist" siglist_b :: Ptr CString -- -- Main.hs {-# LANGUAGE ForeignFunctionInterface #-} module Main where import Foreign import Foreign.C import A import B foreign import ccall "&sys_siglist" siglist_main :: Ptr CString main = do putStrLn $ "siglist_a = " ++ show siglist_a putStrLn $ "siglist_b = " ++ show siglist_b putStrLn $ "siglist_main = " ++ show siglist_main peekSiglist "a " siglist_a peekSiglist "b " siglist_b peekSiglist "main" siglist_main peekSiglist name siglist = do ptr <- peekElemOff siglist 2 str <- maybePeek peekCString ptr putStrLn $ "siglist_" ++ name ++ "[2] = " ++ show str I would expect something like this output, where all pointer values identical and valid: $ runhaskell Main.hs siglist_a = 0x00007f53a948fe00 siglist_b = 0x00007f53a948fe00 siglist_main = 0x00007f53a948fe00 siglist_a [2] = Just "Interrupt" siglist_b [2] = Just "Interrupt" siglist_main[2] = Just "Interrupt" However, if I compile A.hs (with ghc -c A.hs), then the output changes to: $ runhaskell Main.hs siglist_a = 0x0000000040378918 siglist_b = 0x00007fe7c029ce00 siglist_main = 0x00007fe7c029ce00 siglist_a [2] = Nothing siglist_b [2] = Just "Interrupt" siglist_main[2] = Just "Interrupt"

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  • What am I doing wrong with this use of StructLayout( LayoutKind.Explicit ) when calling a PInvoke st

    - by csharptest.net
    The following is a complete program. It works fine as long as you don't uncomment the '#define BROKEN' at the top. The break is due to a PInvoke failing to marshal a union correctly. The INPUT_RECORD structure in question has a number of substructures that might be used depending on the value in EventType. What I don't understand is that when I define only the single child structure of KEY_EVENT_RECORD it works with the explicit declaration at offset 4. But when I add the other structures at the same offset the structure's content get's totally hosed. //UNCOMMENT THIS LINE TO BREAK IT: //#define BROKEN using System; using System.Runtime.InteropServices; class ConIOBroken { static void Main() { int nRead = 0; IntPtr handle = GetStdHandle(-10 /*STD_INPUT_HANDLE*/); Console.Write("Press the letter: 'a': "); INPUT_RECORD record = new INPUT_RECORD(); do { ReadConsoleInputW(handle, ref record, 1, ref nRead); } while (record.EventType != 0x0001/*KEY_EVENT*/); Assert.AreEqual((short)0x0001, record.EventType); Assert.AreEqual(true, record.KeyEvent.bKeyDown); Assert.AreEqual(0x00000000, record.KeyEvent.dwControlKeyState & ~0x00000020);//strip num-lock and test Assert.AreEqual('a', record.KeyEvent.UnicodeChar); Assert.AreEqual((short)0x0001, record.KeyEvent.wRepeatCount); Assert.AreEqual((short)0x0041, record.KeyEvent.wVirtualKeyCode); Assert.AreEqual((short)0x001e, record.KeyEvent.wVirtualScanCode); } static class Assert { public static void AreEqual(object x, object y) { if (!x.Equals(y)) throw new ApplicationException(); } } [DllImport("Kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true)] public static extern IntPtr GetStdHandle(int nStdHandle); [DllImport("Kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true)] public static extern bool ReadConsoleInputW(IntPtr hConsoleInput, ref INPUT_RECORD lpBuffer, int nLength, ref int lpNumberOfEventsRead); [StructLayout(LayoutKind.Explicit)] public struct INPUT_RECORD { [FieldOffset(0)] public short EventType; //union { [FieldOffset(4)] public KEY_EVENT_RECORD KeyEvent; #if BROKEN [FieldOffset(4)] public MOUSE_EVENT_RECORD MouseEvent; [FieldOffset(4)] public WINDOW_BUFFER_SIZE_RECORD WindowBufferSizeEvent; [FieldOffset(4)] public MENU_EVENT_RECORD MenuEvent; [FieldOffset(4)] public FOCUS_EVENT_RECORD FocusEvent; //} #endif } [StructLayout(LayoutKind.Sequential)] public struct KEY_EVENT_RECORD { public bool bKeyDown; public short wRepeatCount; public short wVirtualKeyCode; public short wVirtualScanCode; public char UnicodeChar; public int dwControlKeyState; } [StructLayout(LayoutKind.Sequential)] public struct MOUSE_EVENT_RECORD { public COORD dwMousePosition; public int dwButtonState; public int dwControlKeyState; public int dwEventFlags; }; [StructLayout(LayoutKind.Sequential)] public struct WINDOW_BUFFER_SIZE_RECORD { public COORD dwSize; } [StructLayout(LayoutKind.Sequential)] public struct MENU_EVENT_RECORD { public int dwCommandId; } [StructLayout(LayoutKind.Sequential)] public struct FOCUS_EVENT_RECORD { public bool bSetFocus; } [StructLayout(LayoutKind.Sequential)] public struct COORD { public short X; public short Y; } } UPDATE: For those worried about the struct declarations themselves: bool is treated as a 32-bit value the reason for offset(4) on the data is to allow for the 32-bit structure alignment which prevents the union from beginning at offset 2. Again, my problem isn't making PInvoke work at all, it's trying to figure out why these additional structures (supposedly at the same offset) are fowling up the data by simply adding them.

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  • template specialization of a auto_ptr<T>

    - by Chris Kaminski
    Maybe I'm overcomplicating things, but then again, I do sort of like clean interfaces. Let's say I want a specialization of auto_ptr for an fstream - I want a default fstream for the generic case, but allow a replacement pointer? tempate <> class auto_ptr<fstream> static fstream myfStream; fstream* ptr; public: auto_ptr() { // set ptr to &myfStream; } reset(fstream* newPtr) { // free old ptr if not the static one. ptr = newPtr }; } Would you consider something different or more elegant? And how would you keep something like the above from propagating outside this particular compilation unit? [The actual template is a boost::scoped_ptr.] EDIT: It's a contrived example. Ignore the fstream - it's about providing a default instance of object for an auto_ptr. I may not want to provide a specialized instance, but would like to keep the auto_ptr semantics for this static default object. class UserClass { public: auto_ptr<fstream> ptr; UserClass() { } } I may not provide an dynamic object at construction time - I still want it to have a meaningful default. Since I'm not looking at ownership-transfer semantics, it really shouldn't matter that my pointer class is pointing to a statically allocated object, no?

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  • Destroying a record via RJS TemplateError (Called ID for nil...)

    - by bgadoci
    I am trying to destroy a record in my table via RJS and having some trouble. I have successfully implemented this before so can't quite understand what is not working here. Here is the setup: I am trying to allow a user of my app to select an answer from another user as the 'winning' answer to their question. Much like StackOverflow does. I am calling this selected answer 'winner'. class Winner < ActiveRecord::Base belongs_to :site belongs_to :user belongs_to :question validates_uniqueness_of :user_id, :scope => [:question_id] end I'll spare you the reverse has_many associations but I believe they are correct (I am using has_many with the validation as I might want to allow for multiple later). Also, think of site like an answer to the question. My link calling the destroy action of the WinnersController is located in the /views/winners/_winner.html.erb and has the following code: <% div_for winner do %> Selected <br/> <%=link_to_remote "Destroy", :url => winner, :method => :delete %> <% end %> This partial is being called by another partial `/views/sites/_site.html.erb and is located in this code block: <% if site.winners.blank? %> <% remote_form_for [site, Winner.new] do |f| %> <%= f.hidden_field :question_id, :value => @question.id %> <%= f.hidden_field :winner, :value => "1" %> <%= submit_tag "Select This Answer" %> Make sure you unselect any previously selected answers. <% end %> <% else %> <div id="winner_<%= site.id %>" class="votes"> <%= render :partial => site.winners%> </div> <% end %> <div id="winner_<%= site.id %>" class="votes"> </div> And the /views/sites/_site.html.erb partial is being called in the /views/questions/show.html.erb file. My WinnersController#destroy action is the following: def destroy @winner = Winner.find(params[:id]) @winner.destroy respond_to do |format| format.html { redirect_to Question.find(params[:post_id]) } format.js end end And my /views/winners/destroy.js.rjs code is the following: page[dom_id(@winner)].visual_effect :fade I am getting the following error and not really sure where I am going wrong: Processing WinnersController#destroy (for 127.0.0.1 at 2010-05-30 16:05:48) [DELETE] Parameters: {"authenticity_token"=>"nn1Wwr2PZiS2jLgCZQDLidkntwbGzayEoHWwR087AfE=", "id"=>"24", "_"=>""} Rendering winners/destroy ActionView::TemplateError (Called id for nil, which would mistakenly be 4 -- if you really wanted the id of nil, use object_id) on line #1 of app/views/winners/destroy.js.rjs: 1: page[dom_id(@winner)].visual_effect :fade app/views/winners/destroy.js.rjs:1:in `_run_rjs_app47views47winners47destroy46js46rjs' app/views/winners/destroy.js.rjs:1:in `_run_rjs_app47views47winners47destroy46js46rjs' Rendered rescues/_trace (137.1ms) Rendered rescues/_request_and_response (0.3ms) Rendering rescues/layout (internal_server_error)

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  • C++ converting binary(P5) image to ascii(P2) image (.pgm)

    - by tubby
    I am writing a simple program to convert grayscale binary (P5) to grayscale ascii (P2) but am having trouble reading in the binary and converting it to int. #include <iostream> #include <fstream> #include <sstream> using namespace::std; int usage(char* arg) { // exit program cout << arg << ": Error" << endl; return -1; } int main(int argc, char* argv[]) { int rows, cols, size, greylevels; string filetype; // open stream in binary mode ifstream istr(argv[1], ios::in | ios::binary); if(istr.fail()) return usage(argv[1]); // parse header istr >> filetype >> rows >> cols >> greylevels; size = rows * cols; // check data cout << "filetype: " << filetype << endl; cout << "rows: " << rows << endl; cout << "cols: " << cols << endl; cout << "greylevels: " << greylevels << endl; cout << "size: " << size << endl; // parse data values int* data = new int[size]; int fail_tracker = 0; // find which pixel failing on for(int* ptr = data; ptr < data+size; ptr++) { char t_ch; // read in binary char istr.read(&t_ch, sizeof(char)); // convert to integer int t_data = static_cast<int>(t_ch); // check if legal pixel if(t_data < 0 || t_data > greylevels) { cout << "Failed on pixel: " << fail_tracker << endl; cout << "Pixel value: " << t_data << endl; return usage(argv[1]); } // if passes add value to data array *ptr = t_data; fail_tracker++; } // close the stream istr.close(); // write a new P2 binary ascii image ofstream ostr("greyscale_ascii_version.pgm"); // write header ostr << "P2 " << rows << cols << greylevels << endl; // write data int line_ctr = 0; for(int* ptr = data; ptr < data+size; ptr++) { // print pixel value ostr << *ptr << " "; // endl every ~20 pixels for some readability if(++line_ctr % 20 == 0) ostr << endl; } ostr.close(); // clean up delete [] data; return 0; } sample image - Pulled this from an old post. Removed the comment within the image file as I am not worried about this functionality now. When compiled with g++ I get output: $> ./a.out a.pgm filetype: P5 rows: 1024 cols: 768 greylevels: 255 size: 786432 Failed on pixel: 1 Pixel value: -110 a.pgm: Error The image is a little duck and there's no way the pixel value can be -110...where am I going wrong? Thanks.

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  • c++-to-python swig caused memory leak! Related to Py_BuildValue and SWIG_NewPointerObj

    - by usfree74
    Hey gurus, I have the following Swig code that caused memory leak. PyObject* FindBestMatch(const Bar& fp) { Foo* ptr(new Foo()); float match; // call a function to fill the foo pointer return Py_BuildValue( "(fO)", match, SWIG_NewPointerObj(ptr, SWIGTYPE_p_Foo, 0 /* own */)); } I figured that ptr is not freed properly. So I did the following: PyObject* FindBestMatch(const Bar& fp) { Foo* ptr(new Foo()); float match; // call a function to fill the foo pointer *PyObject *o = SWIG_NewPointerObj(ptr, SWIGTYPE_p_Foo, 1 /* own */);* <------- 1 means pass the ownership to python PyObject *result = Py_BuildValue("(fO)", match, o); Py_XDECREF(o); return result; } But I am not very sure whether this will cause memory corruption. Here, Py_XDECREF(o) will decrease the ref count, which can free memory used by object "o". But o is part of the return value "result". Freeing "o" can cause data corrupt, I guess? I tried my change. It works fine and the caller (python code) does see the expected data. But this could be because nobody else overwrites to that memory area. So what's the right way to deal with memory management of the above code? I search the swig docs, but don't see very concrete description. Please help! Thanks, xin

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  • Dangling pointer

    - by viswanathan
    Does this piece of code lead to dangling pointer. My guess is no. class Sample { public: int *ptr; Sample(int i) { ptr = new int(i); } ~Sample() { delete ptr; } void PrintVal() { cout << "The value is " << *ptr; } }; void SomeFunc(Sample x) { cout << "Say i am in someFunc " << endl; } int main() { Sample s1 = 10; SomeFunc(s1); s1.PrintVal(); }

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  • How to access class member from bison action

    - by yodhevauhe
    I am calling yyparse from a member function. How to access the member variables/function from the bison action. I am currently doing as %{ #include "myclass.h" #include "parse.tab.hh" MyClass *ptr=NULL; void MyClass::evaluate(string expression) { ptr=this; yy_scan_string(expression.c_str()); yyparse(); } %} %% EXPR : EXPR PLUS EXPR { $$ = ptr->memberFunction("+",$1,$3); }

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  • Cutting large XML file into smaller pieces in C#

    - by NDraskovic
    I have a problem that I'm working on for quite some time now. I have an XML file with over 50000 records (one record has 3 levels). This file is used by one of my applications to control document sending (the record holds, among other informations, the type of document that has to be sent to a certain person). So in my application I load the XML file into a XmlDocument, and then by using SelectNodes method, I create a XmlNodeList from which I read the data I want. The process is like this - our worker takes the persons ID card (simple eith barcode) and reads it with barcode reader. When the barcode value has been read, my application finds the person with that ID in the XML file, and stores the type of the document into a string variable. Then the worker takes the document and reads its barcode, and if the value of documents barcode and the value in the value in the string variable match, the application makes a record that document of type xxxxxxxx will be sent to the person with ID yyyyyyyyy. This is very simple code, it works perfectly for now, and this is how it looks: On textBox1_TextChanged event (worker read persons ID): foreach(XmlNode node in NodeList){ if(String.Compare(node.Attributes.GetNamedItem("ID").Value.ToString(),textBox1.Text)==0) { ControlString = node.ChildNode[3].FirstChild.Attributes.GetNamedItem("doctype").Value.ToString(); break; } } textBox2.Focus(); And on textBox2_TextChanged event (worker read the documents barcode): if(String.Compare(textBox2.Text,ControlString)==0) { //Create a record and insert it into a SQL database } My question is - how will my application perform with larger XML files (I was told that the XML file might be up to 500,000 records large), will this approach be valid, or will I need to cut the file into smaller files. If I have to cut it, please give me an idea with some code samples, I've tried to do it like this: Reading entire record and storing it into a string: private void WriteXml(XmlNode record) { tempXML = record.InnerXml; temp = "<" + record.Name + " code=\"" + record.Attributes.GetNamedItem("code").Value + "\">" + Environment.NewLine; temp += tempXML + Environment.NewLine; temp += "</" + record.Name + ">"; SmallerXMLDocument += temp + Environment.NewLine; temp = ""; i++; } tempXML, temp and SmallerXMLDocument are all string variables. And then in button_Click method I load the XML file into a XmlNodeList (again by using XmlDocument.SelectNodes method) and I try to create one big string value that would hold all records like this: foreach(XmlNode node in nodes) { if(String.Compare(node.ChildNode[3].FirstChild.Attributes.GetNamedItem("doctype").Value.ToString(),doctype1)==0) { WriteXML(node); } } My idea was to create a string value (in this case called SmallerXmlDocument), and when I pass trough the entire XML file, to simply copy the value of that string into a new file. This works, but only for files that have up to 2000 records (and my has way more than that). So, if I need to cut the file into smaller pieces, what would be the best way to do it (keep in mind that there could be up to half a million records in a XML file)? Thanks

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