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  • How could my code compliled correctly without necessary headers?

    - by ZhengZhiren
    I use the functions fork(),exec()... But how can this program compiled without including some extra headers(like sys/types.h, sys/wait.h). I use ubuntu 10.04 with gcc version 4.4.3 #include <stdio.h> #include <stdlib.h> int main() { pid_t pid; printf("before fork\n"); pid = fork(); if(pid == 0) { /*child*/ if(execvp("./cpuid", NULL)) { printf("error\n"); exit(0); } } else { if(wait(NULL) != -1) { printf("ok\n"); } } return 0; }

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  • How to draw multiple line text to uiimageview iphone?

    - by Hu?nh Phong
    I have UITextView for text, after user press DONE, I convert text to UIImageView and show it. It works with one line of text very good, and Screenshot 1 . But if user types two lines, or more: the result is still one line??? Screenshot 2 I want to display two or more lines in UIimageView Can anybody help me! Thank you very much! Here is my code: -(UIImage *)convertTextToImage : (ObjectText *) objT; { UIGraphicsBeginImageContext(CGSizeMake(([objT.content sizeWithFont:objT.font].width+10), ([objT.content sizeWithFont:objT.font].height+10))); [[objT getcolor] set]; [objT.content drawAtPoint:CGPointMake(5, 5) withFont:objT.font]; UIImage *result = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return result; }

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  • Bug in variadic function template specialization with MSVC?

    - by Andrei Tita
    Using the Visual Studio Nov 2012 CTP, which supports variadic templates (among other things). The following code: template<int, typename... Args> void myfunc(Args... args) { } template<> void myfunc<1, float>(float) { } produces the following errors: error C2785: 'void myfunc(Args...)' and 'void myfunc(float)' have different return types error C2912: explicit specialization 'void myfunc(float)' is not a specialization of a function template (yeah, the first one is pretty funny) So my questions are: 1) Am I writing legal C++11 here? 2) If yes, is there a way to find out if this is a known bug in MSVC before submitting it?

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  • If I'm projecting with linq and not using a range variable what is the proper syntax?

    - by itchi
    I have a query that sums and aggregates alot of data something like this: var anonType = from x in collection let value = collection.Where(c=>c.Code == "A") select new { sum = value.Sum(v=>v.Amount) }; I find it really weird that I have to declare the range variable x, especially if I'm not using it. So, am I doing something wrong or is there a different format I should be following? Also, keep in mind that anonType has about 15 different properties that are all types of aggregates (sums,counts, etc). So I couldn't do something like: int x = collection.Where(c=>c.Code == "A").Sum(v=>v.Amount);

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  • Java: How to get Unicode name of a character (or its type category)?

    - by java.is.for.desktop
    Hello, everyone! The Character class in Java defines methods which check a given char argument for equality with certain Unicode chars or for belonging to some type category. These chars and type categories are named. As stated in given javadoc, examples for named chars are HORIZONTAL TABULATION, FORM FEED, ...; example for named type categories are SPACE_SEPARATOR, PARAGRAPH_SEPARATOR, ... However, being byte or int values instead of enums, the name of these types are "hidden" at runtime. So, is there a possibility to get characters' and/or type categories' names at runtime?

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  • Results from two queries at once in sqlite?

    - by SF.
    I'm currently trying to optimize the sluggish process of retrieving a page of log entries from the SQLite database. I noticed I almost always retrieve next entries along with count of available entries: SELECT time, level, type, text FROM Logs WHERE level IN (%s) ORDER BY time DESC, id DESC LIMIT LOG_REQ_LINES OFFSET %d* LOG_REQ_LINES ; together with total count of records that can match current query: SELECT count(*) FROM Logs WHERE level IN (%s); (for a display "page n of m") I wonder, if I could concatenate the two queries, and ask them both in one sqlite3_exec() simply concatenating the query string. How should my callback function look then? Can I distinguish between the different types of data by argc? What other optimizations would you suggest?

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  • How to ensure consistency of enums in Java serialization?

    - by Uri
    When I serialize an object, I can use the serialVersionUID mechanism at the class level to ensure the compatibility of the two types. However, what happens when I serialize fields of enum values? Is there a way to ensure that the enum type has not been manipulated between serialization and deserialization? Suppose that I have an enum like OperationResult {SUCCESS, FAIL}, and a field called "result" in an object that is being serialized. How do I ensure, when the object is deserialized, that result is still correct even if someone maliciously reversed the two? (Suppose the enum is declared elsewhere as a static enum) I am wondering out of curiosity - I use jar-level authentication to prevent manipulation.

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  • What are the disadvantages of using a StringBuilder?

    - by stickman
    I know that StringBuilder is more efficient than a normal string when processing code which modifies the string value a lot because although strings act like value types, they are actually reference, which makes them immutable so every time we change it, we need to create a new reference in memory. My question is that, why doesn't .NET just use stringBuilder by default? There must be some disadvantages of it over just using String. Can anyone tell me what they are? The only thing I can think of is perhaps it is a heavier object and it takes more time to instantiate so if you aren't changing the string too much, this would override the benefits of StringBuilder

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  • No mapping for LONGVARCHAR in Hibernate 3.2

    - by jimbokun
    I am running Hibernate 3.2.0 with MySQL 5.1. After updating the group_concat_max_len in MySQL (because of a group_concat query that was exceeding the default value), I got the following exception when executing a SQLQuery with a group_concat clause: "No Dialect mapping for JDBC type: -1" -1 is the java.sql.Types value for LONGVARCHAR. Evidently, increasing the group_concat_max_len value causes calls to group_concat to return a LONGVARCHAR value. This appears to be an instance of this bug: http://opensource.atlassian.com/projects/hibernate/browse/HHH-3892 I guess there is a fix for this issue in Hibernate 3.5, but that is still a development version, so I am hesitant to put it into production, and don't know if it would cause issues for other parts of my code base. I could also just use JDBC queries, but then I have to replace every instance of a SQLQuery with a group_concat clause. Any other suggestions?

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  • returning null or throwing an exception?

    - by MoKi
    I have the following types: typedef QPair < QTime , QTime > CalculatedTimeSlotRange; typedef QList < CalculatedTimeSlotRange > CalculatedTimeSlotRangeList; typedef QHash < quint8 , CalculatedTimeSlotRangeList > TimeSlotsTable; I have a function like the following: const CalculatedTimeSlotRangeList* TimeSlots::getCalculatedTimeSlotRangeList(const quint8 id) const { QHashIterator<quint8,CalculatedTimeSlotRangeList> it(mTimeSlotsTable); while (it.hasNext()) { it.next(); if(it.key() == id) { return &it.value(); } } return NULL; } as you can see my function returns a null if it fails to find a key that matches id. Is this correct? or should I just throw an exception if the key does not exist? how should i throw an exception for this situation?

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  • Separating MySQL SELECT statement based on data in a column

    - by NightMICU
    Hi everyone, I need to retrieve data (vehicle details, in this case) from a MySQL table tabled and then loop through the results to generate separate lists for each category of vehicle. Is there a simple way to do this without having to have a SELECT statement for each type of vehicle? If I were just doing this for one category, I would use the following: <?php $sql = "SELECT * FROM apparatus WHERE vehicleType = 'Support'; $getSQL = mysql_query($sql); ?> <ul> <?php while ($vehicleData = mysql_fetch_assoc($getSQL)) {?> <li><?php echo $vehicleData['name'];?></li> <?php } ?> </ul> ..etc. Need to do this for four different types of vehicles. Thanks!

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  • Check constraint on table lookup

    - by bzamfir
    Hi, I have a table, department , with several bit fields to indicate department types One is Warehouse (when true, indicate the department is warehouse) And I have another table, ManagersForWarehouses with following structure: ID autoinc WarehouseID int (foreign key reference DepartmentID from departments) ManagerID int (foreign key reference EmployeeID from employees) StartDate EndDate To set new manager for warehouse, I insert in this table with EndDate null, and I have a trigger that sets EndDate for previous record for that warehouse = StartDate for new manager, so a single manager appears for a warehouse at a certain time. I want to add two check constraints as follows, but not sure how to do this do not allow to insert into ManagersForWarehouses if WarehouseID is not marked as warehouse Do not allow to uncheck Warehouse if there are records in ManagersForWarehouses Thanks

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  • Is it possible to use inheritance in this situation? (Java)

    - by they changed my name
    I have ClassA and ClassB, with ClassA being the superclass. ClassA uses NodeA, ClassB uses NodeB. First problem: method parameters. ClassB needs NodeB types, but I can't cast from the subclass to the superclass. That means I can't set properties which are unique to NodeB's. Second problem: When I need to add nodes toClassB, I have to instantiate a new NodeB. But, I can't do this in the superclass, so I'd have to rewrite the insertion to use NodeB. Is there a way around it or am I gonna have to rewrite the whole thing?

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  • Using template specialization in C++

    - by user550413
    How can I write a function using template specialization that has 2 different input types and an output type: template <class input1, class input2, class output> and return the sum of the 2 numbers (integers/doubles). However, if I get 2 integers I want to return an integer type but for any other combinations of integer and double I'll always return double. I am trying to do that without using directly the '+' operator but having the next functions instead: double add_double_double(double a, double b) {return (a+b);} double add_int_double(int a, double b) {return ((double)(a)+b);} int add_int_int(int a, int b) {return (a+b);}

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  • ASP.Net website makes browser load unwanted (non-referenced) plugins

    - by alec0001
    I've found that some of my ASP.Net web apps prompt the browser to load plugins that I'm not explicitely using and certainly haven't deliberately referenced in the project settings. Two that come to mind are for MS MediaPlayer and the "SVG Viewer for Netscape". The only commonality I've determined so far is that the two sites/apps affected both use Master pages (nested in some cases). We don't use SVG file types (just the normal mix of jpg/gif/png) and no video/audio (not yet anyway). Can anyone provide a hint as to where the references for these might be creeping in? e.g. Is it a server-level include? Or a .Net runtime default when using master pages? Does anyone else even experience this, or is it just me? No urgency, I'd just like to remove it if possible. Thanks. Al

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  • Consolidating separate Loan, Purchase & Sales tables into one transaction table.

    - by Frank Computer
    INFORMIX-SE with ISQL 7.3: I have separate tables for Loan, Purchase & Sales transactions. Each tables rows are joined to their respective customer rows by: customer.id [serial] = loan.foreign_id [integer]; = purchase.foreign_id [integer]; = sale.foreign_id [integer]; I would like to consolidate the three tables into one table called "transaction", where a column "transaction.trx_type" [char(1)] {L=Loan, P=Purchase, S=Sale} identifies the transaction type. Is this a good idea or is it better to keep them in separate tables? Storage space is not a concern, I think it would be easier programming & user=wise to have all types of transactions under one table.

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  • Customers and suppliers database design issue

    - by hectorsq
    I am developing a web application in which I will have customers and suppliers. Initially I thought on using a Customers table and a Suppliers table. Then when I was thinking on bank transactions, I noticed that each transaction needs to refer to a customer or a supplier, so I thought on using a single table named Business in which I will save both customers and suppliers. If I use Customers and Suppliers tables when I want to list the bank transactions I will have to search in both tables to get the company name. If I use a Businesses table I will have to use a business type column, and have the union of possible fields for all businesses types. Any suggestions on the design?

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  • C++ enforce conditions on inherited classes

    - by user231536
    I would like to define an abstract base class X and enforce the following: a) every concrete class Y that inherits from X define a constructor Y(int x) b) it should be possible to test whether two Y objects are equal. For a, one not very good solution is to put a pure virtual fromInt method in X which concrete class will have to define. But I cannot enforce construction. For b), I cannot seem to use a pure virtual method in X bool operator == (const X& other) const =0; because in overridden classes this remains undefined. It is not enough to define bool operator == (const Y& other) const { //stuff} because the types don't match. How do I solve these problems?

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  • submit button on html to output result on same page

    - by amateur
    Hi, Although this seems like something very basic, but no matter what I tried I couldn't get my head around it. Basically I want a html form where a user types in their ID number in an input text box and when they hit the submit button it displays their email address which is their company ID number @ company.com, such as below <form action=""> ID Number: <input type="text" name="idnumber" /><br/> <input type="submit" value="Whats my email address" /> </form> <p>Your email address is 'idnumber'@email.com</p> Can this even be done using html or would I need to use Javascript or PHP for it? Thanks

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  • Offsite data storage for simple app, or a similar supported persistence mechanism?

    - by jdk
    Question Is there a usable facebook entry point to the Data Storage API that facebook lists on their app admin page for developers, or should I consider an alternate mechanism? What alternative mechanisms exist to simply persist my information offsite (away from my server app) without stuffing it into a cookie that's prone to expire? ... Background The facebook Data Store Admin tool is made available in a facebook App's Settings as seen here: (continue reading below) However when I visit the DataStoreAdmin link nothing works (i.e. clicking the buttons to define the data store types and objects does nothing - I have tried different browsers). The Wiki page for Data Store API hasn't been updated recently and the second last update says the beta Data Store was taken offline. It seems odd the link would be readily available and highly visible at the top of the App configuration area if indeed it's defunct. I was hoping some kind of key/value pair solution to remove the data calls from my own server.

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  • Composite pattern in C++ problem

    - by annouk
    Hello! I have to work with an application in C++ similar to a phone book: the class Agenda with an STL list of Contacts.Regarding the contacts hierarchy,there is a base-class named Contact(an abstract one),and the derived classes Friend and Acquaintance(the types of contact). These classes have,for instance, a virtual method called getName,which returns the name of the contact. Now I must implement the Composite pattern by adding another type of contact,Company(being derived from Contact),which also contains a collection of Contacts(an STL list as well),that can be either of the "leaf" type(Friends or Acquaintances),or they can be Companies as well. Therefore,Company is the Compound type. The question is: how and where can I implement an STL find_if to search the contact with a given name(via getName function or suggest me smth else) both among the "leaf"-type Contact and inside the Company collection? In other words,how do I traverse the tree in order to find possible matches there too,using an uniform function definition? I hope I was pretty clear...

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  • best way to write a-> ..->[a] recursive functions in haskell

    - by Roman A. Taycher
    So I keep having this small problem where I have something like func :: a -> b -> [a] -- or basically any a-> ...-> [a] where ... is any types -> func x y = func' [x] y -- as long as they are used to generate a list of [a] from x func' :: [a] -> b -> [a] func = undefined --situation dependant generates a list from each element and returns it as one long list should I keep it like this? should I use func' hidden by a where? should I only use the [a] - b - [a] version and leave the responsibility of passing [variable] to the callee? I might well need to compose these functions and might want to mess around with the order so I'm leaning towards option 3. What do you think?

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  • How to coerce type of ActiveRecord attribute returned by :select phrase on joined table?

    - by tribalvibes
    Having trouble with AR 2.3.5, e.g.: users = User.all( :select => "u.id, c.user_id", :from => "users u, connections c", :conditions => ... ) Returns, e.g.: => [#<User id: 1000>] >> users.first.attributes => {"id"=>1000, "user_id"=>"1000"} Note that AR returns the id of the model searched as numeric but the selected user_id of the joined model as a String, although both are int(11) in the database schema. How could I better form this type of query to select columns of tables backing multiple models and retrieving their natural type rather than String ? Seems like AR is punting on this somewhere. How could I coerce the returned types at AR load time and not have to tack .to_i (etc.) onto every post-hoc access?

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  • Problems with ActiveRecord assoc

    - by ciss
    Hello again, so i write my e-commerce shop cms and have some strange error: ActiveRecord::StatementInvalid: Mysql::Error: Unknown column 'id' in 'where clause': DELETE FROM `properties` WHERE `id` = NULL so, i have three models Items: class Item < ActiveRecord::Base has_many :properties, :dependent => :destroy has_many :types, :through => :property end Type: class Type < ActiveRecord::Base has_many :properties, :dependent => :destroy end Properties: class Property < ActiveRecord::Base belongs_to :item belongs_to :type end So, all is okay, but when i try to item.destroy() i have error =( This is my test code: test "should destroy associated properties" do item = Item.create(:name => "Jeans") type = Type.create(:key => "color") property = Property.new property.item = item property.type = type property.save item.destroy() end

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  • How does ‘Servers’ view work underlying in Eclipse?

    - by Michael Lu
    ‘Servers’ is built-in view in Eclipse. We could integrate jee server into Eclipse easily. It could start/stop server both in normal and debug modes. Moreover, we could even set timeout and deployment path, things like that. Various types of server tomcat, jboss, websphere are supported, no intrusive to server. I am just curious about how these cool things happen behind the scene. The complete mechanism is large and complex, so I just want to know general mechanism about it, an article also could be fine for me. Thank you!

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