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  • using logos in asp .net

    - by program-java
    hii I m creating a web site in that i want some logos for website what can i used to develop logos which can easily support to my web site also i want set back ground of image as my pages 's back ground.

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  • Python: NameError: 'self' is not defined

    - by Rosarch
    I must be doing something stupid. I'm running this in Google App Engine: def render(self, template_name, template_data): path = os.path.join(os.path.dirname(__file__), 'static/templates/%s.html' % template_name) self.response.out.write(template.render(path, template_data)) This gives an error: Traceback (most recent call last): File "C:\Program Files\Google\google_appengine\google\appengine\tools\dev_appserver.py", line 3192, in _HandleRequest self._Dispatch(dispatcher, self.rfile, outfile, env_dict) File "C:\Program Files\Google\google_appengine\google\appengine\tools\dev_appserver.py", line 3135, in _Dispatch base_env_dict=env_dict) File "C:\Program Files\Google\google_appengine\google\appengine\tools\dev_appserver.py", line 516, in Dispatch base_env_dict=base_env_dict) File "C:\Program Files\Google\google_appengine\google\appengine\tools\dev_appserver.py", line 2394, in Dispatch self._module_dict) File "C:\Program Files\Google\google_appengine\google\appengine\tools\dev_appserver.py", line 2304, in ExecuteCGI reset_modules = exec_script(handler_path, cgi_path, hook) File "C:\Program Files\Google\google_appengine\google\appengine\tools\dev_appserver.py", line 2200, in ExecuteOrImportScript exec module_code in script_module.__dict__ File "main.py", line 22, in <module> class MainHandler(webapp.RequestHandler): File "main.py", line 38, in MainHandler self.writeOut(template.render(path, template_data)) NameError: name 'self' is not defined What am I doing wrong?

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  • IIS7.5 and MVC 2 : Implementing HTTP(S) security

    - by Program.X
    This is my first ASP.NET MVC application, and my first on an IIS 7.x installation whereby I have to do anything over and above the standard. I need to enforce Windows authentication on the /Index and /feeds/xxx.svc pages/services. In ASP.NET Web Forms, I would apply the Windows permissions on the files and remove Anonymous authentication in IIS 6. This needs to work over HTTP/S, but don't worry about that, that's in hand. What happens in MVC/IIS 7? I have tried modifying the permissions on the /Index.aspx view, which seems to block access. It asks me for a username/password, but does not grant access when I enter a valid username/password. Pressing Escape gives me an exception "*Access to the path 'E:\dev\xxx\xxx.ConsultantRegistration.Web.Admin\Views\ConsultantRegistration\index.aspx' is denied. *", which does get sent as a 401. So although the username/password does exist on the Index.aspx view, I can't use those credentials to access said view. I have in my web.config: What am I missing?

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  • How can I close my software in a save way?

    - by Roman
    Up to now I used my application as a stand alone product. So, when user pressed "Stop" button I called System.exit(0); and it was fine. Now my application will be called (in a programmatic way) from another program. So, I afraid that System.exit(0); will kill not only my process but also the external software which started my program. So, what is the correct way to shutdown my application if a corresponding request from an external software is received? My application is an GUI application. So, I want to close the window but I also want to close all processes performed by my program. ADDED: To be more specific, I want to close all threads started by my program. My program does not start any OS process or any other program.

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  • Clojure warn-on-reflection and type hints

    - by Ralph
    In the following code, I am getting a warning on reflection: (ns com.example (:import [org.apache.commons.cli CommandLine Option Options PosixParser])) (def *help-option* "help") (def *host-option* "db-host") (def *options* (doto (Options.) (.addOption "?" *help-option* false "Show this usage information") (.addOption "h" *host-option* true "Name of the database host"))) (let [^CommandLine command-line (.. (PosixParser.) (parse *options* (into-array String args))) db-host (.getOptionValue command-line "h")] ; WARNING HERE ON .getOptionValue ; Do stuff with db-host ) I have a type hint on command-line. Why the warning? I am using Clojure 1.2 on OS X 10.6.6 (Apple VM). I assume that I do not get a warning on (.addOption ...) because the compiler knows that (Options.) is a org.apache.commons.cli.Options).

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  • Export environment variable from PHP, for use by exec()'d shell command?

    - by anonymous coward
    Somewhat similar to http://stackoverflow.com/questions/2002970/export-a-variable-from-php-to-shell, but my problem is different. I am forced to work with a program that gets an important location variable from an Environment Variable (Linux), rather than a config or, better, a command line option. I have to call this program from within PHP, and currently am doing it like so: shell_exec('/path/to/program option1 option2'); I need to be able to set/override the environment variable that program will be looking for. As an example, this does not work: shell_exec('VAR1=foo /path/to/program option1 option2'); nor does: shell_exec('VAR1=foo; export foo; /path/to/program option1 option2'); for good measure. Both of the above command lines work "as expected" from the shell. Is it possible to override environment variables for programs called via exec, shell_exec, etc?

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  • Regular Expression to capture the first <p> of HTML

    - by Program.X
    I have the following regular expression: (?:<(?<tag>\w*)>(?<text>.*)</\k<tag>>) I want it t grab the text within the first HTML element. eg. <p>This should capture</p>This shouldn't Works, but ... <p>This should capture</p><p>This shouldn't</p> Doesn't work. As you'd expect, it returns: This should capture</p><p>This shouldn't I'm racking my brains here. How can I just have it select the FIRST inner text? (I'm trying to be tag-agnostic, so <strong>This should match</strong> is equally appropriate, etc.)

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  • Change the for loop with lambda(C#3.0)

    - by Newbie
    Is it possible to do the same using Lambda for (int i = 0; i < objEntityCode.Count; i++) { options.Attributes[i] = new EntityCodeKey(); options.Attributes[i].EntityCode = objEntityCode[i].EntityCodes; options.Attributes[i].OrganizationCode = Constants.ORGANIZATION_CODE; } I mean to say to rewrite the statement using lambda. I tried with Enumerable.Range(0,objEntityCode.Count-1).Foreach(i=> { options.Attributes[i] = new EntityCodeKey(); options.Attributes[i].EntityCode = objEntityCode[i].EntityCodes; options.Attributes[i].OrganizationCode = Constants.ORGANIZATION_CODE; }); but not working I am using C#3.0

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  • How to set baud rate to 307200 on Linux?

    - by cairol
    Basically I'm using the following code to set the baud rate of a serial port: struct termios options; tcgetattr(fd, &options); cfsetispeed(&options, B115200); cfsetospeed(&options, B115200); tcsetattr(fd, TCSANOW, &options); This works very well. But know I have to communicate with a device that uses a baud rate of 307200. How can I set that? cfsetispeed(&options, B307200); doesn't work, there is no B307200 defined.

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  • Empty files generated from running `mysqldump` using PHP

    - by alex
    I keep getting empty files generated from running $command = 'mysqldump --opt -h localhost -u username -p \'password\' dbname > \'backup 2009-04-15 09-57-13.sql\''; command($command); Anyone know what might be causing this? My password has strange characters in it, but works fine with connecting to the db. I've ran exec($command, $return) and outputted the $return array and it is finding the command. I've also ran it with mysqldump > file.sql and the file contains Usage: mysqldump [OPTIONS] database [tables] OR mysqldump [OPTIONS] --databases [OPTIONS] DB1 [DB2 DB3...] OR mysqldump [OPTIONS] --all-databases [OPTIONS] For more options, use mysqldump --help So it would seem like the command is working.

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  • DropDownList not working 100% in ASP.Net MVC

    - by Program.X
    I am quite confused with how to effectively use the Html.DropDownList helper for ASP.NET MVC. Background: I have a 5-page form, which saves data to the form each time "Next" is clicked. Users may navigate back and forth between sections, so previous sections will already be pre-populated with previously-entered data. This works for TextBoxes. But not DropDownLists. I have tried a load of different methods, including: http://stackoverflow.com/questions/867117/how-to-add-static-list-of-items-in-mvc-html-dropdownlist/867218#867218 http://stackoverflow.com/questions/2080802/setting-selected-item-to-dropdownlist-in-mvc-application I have a ViewModel such taht I have got my lists and my Model (a LINQ-to-SQL generated class) as properties. eg: public class ConsultantRegistrationFormViewModel { public IConsultantRegistration ConsultantRegistration { get; private set; } public SelectList Titles { get; private set; } public SelectList Countries { get; private set; } public SelectList Currencies { get; private set; } public int CurrentSection { get; private set; } private ConsultantRegistrationFormViewModel(IConsultantRegistration consultantRegistration) { ConsultantRegistration = consultantRegistration; CurrentSection = 1; Titles = new SelectList(new string[] { "Mr", "Mrs", "Miss", "Ms", "Dr", "Sir" }); Countries = new SelectList(countries.Select(q => q.Name)); Currencies = new SelectList(currencies,"CurrencyCode","FriendlyForm"); } } My Controller's Edit Action on GET looks like: public class ConsultantRegistrationController : Controller { public IConsultantRegistrationRepository ConsultantRegistrationRepository { get; private set; } public ICountryRepository CountryRepository { get; private set; } public IEnumerable<ICountry> Countries { get; private set; } public ConsultantRegistrationController() { ConsultantRegistrationRepository = RepositoryFactory.CreateConsultantRegistrationRepository(); CountryRepository = RepositoryFactory.CreateCountryRepository(); Countries = CountryRepository.GetCountries().ToArray(); } public ActionResult Edit(Guid id, int sectionIndex) { IConsultantRegistration consultantRegistration = ConsultantRegistrationRepository.GetConsultantRegistration(id); SelectList bankBranchCountriesSelectList = new SelectList(Countries, "BankBranchCountry", "CountryName", consultantRegistration.BankBranchCountry); ViewData["bankBranchCountrySelectList"] = bankBranchCountriesSelectList; return View(new ConsultantRegistrationFormViewModel(consultantRegistration,sectionIndex, Countries,Currencies)); } } With my View doing: <%: Html.DropDownList("ConsultantRegistration.BankBranchCountry",ViewData["bankBranchCountrySelectList"] as SelectList) %> This gives me the error: DataBinding: 'IWW.ArrowPay.ConsultantRegistration.Data.Country' does not contain a property with the name 'BankBranchCountry'. Which it does, have a look at the schema of this property: public interface IConsultantRegistration { Guid ID { get; set; } [DisplayName("Branch Country")] string BankBranchCountry { get; set; } } (My LINQ-to-SQL type ConsultantRegistration implemented IConsultantRegistration) It seems that it is trying to bind to the wrong type, though? If I use this in my view (and use my Controller's Countries property): <%: Html.DropDownList("ConsultantRegistration.BankBranchCountry ",Model.Countries,"(select a Country)") %> I get the saved value fine, but my model doesn't update on POST. And if I use this in my view: <%: Html.DropDownListFor(model=>model.ConsultantRegistration.BankBranchCountry ",Model.Countries,"(select a Country)") %> I get the list, and it POSTs the selected value back, but does not pre-select the currently selected item in my model on the view. So I have a bit of the solution all over the place, but not all in one place. Hope you can help fill in my ignorance.

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  • Moving users folder on Windows-7 to another partition - bad idea?

    - by Donat
    Hi, I'd like to re-submit here a question posted by Benjol on Aug 17at 5:57 "Moving users folder on Windows Vista to another partition - bad idea?" (I can't post one than one link until I earn "10 reputation" and removed my "answer" there to post my follow-up questions here). I am anxiously getting ready at long last to to carry out a clean install (using custom install option) from Vista to Windows-7 Home Premium 64bit with the free upgrade I received late October. For my Vista system I successfully set-up last Summer a multi-partitions scheme with Users and Program Data on a a different partition than the operating system (see link below, and its subsequent links in my comment for details). http://tuts4tech.net/2009/08/05/windows-7-move-the-users-and-program-files-directories-to-a-different-partition/comment-page-1/#comment-562 I was planning a similar set-up for windows 7, a little more streamlined, with OS, Program Files on C:, Users and Program Data on D:, and TV media recording on a separate partition. Reading the Question submitted by Benjol, I am second guessing too. Is moving Users and Program Data on a different partition than the default primary partition with OS and Program Files such a good idea? The couple of people I talked to at the official Microsoft Windows 7 booth at CES 2010 gave the same answer to the intention of moving the Users profile folder to another partition. In a nutshell, they all told me that they used to do this in XP and less in Vista but not anymore with Windows 7... "It is stable, after two months still no problem" I had the feeling it was a scripted answer to emphasize how Windows 7 is so stable and efficient... (Will Windows-7 system not become bugged down over the course of several months to a year or two? Only time will tell) Long story short, I share the same view than Benjol expressed with respect to being "able to backup and restore system and user data independently." I just received a 2TB usb2, eSATA external hard drive as a back-up drive, which includes NTI Shadow 4 (4.1.0.150) for back-up solution. I took note of the issue with NTUSER.DAT and I will read more about Volume Shadow Copy Service (VSS) for Windows 7. I am willing to put the effort if placing Users and Program Data on a different partition would allow to restore a fresher OS+Program image when the system gets bugged down. Questions: Is it such a bad idea? What is the "easy route" referred by Benjol in his post? Is it to just relocate folders to another partition using the Folder property tool? (It is not practical for several users and might not provide a straightforward restore process of just OS and Program Files when needed.) I am starting to learn about Windows 7 libraries. Would Windows 7 libraries be another alternative to achieve this? All this reading to decide how to organize the partition scheme for my custom system is starting to be confusing. I apologize for this lengthy Question. It is my first day here on SuperUser and I am just learning how different from a discussion thread it is. Thank you in advance for all your suggestions and comments. Donat

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  • Openvpn issue with linux

    - by catsy
    So I've tried to setup openvpn, I followed some guide but it's stuck att "initialization sequence completed" with no connection and I can't find any working solution... here's the log: $Sun Sep 23 19:14:32 2012 OpenVPN 2.1.0 i486-pc-linux-gnu [SSL] [LZO2] [EPOLL] [PKCS11] [MH] [PF_INET6] [eurephia] built on Jul 20 2010 Enter Auth Username:pumpedup Enter Auth Password: Sun Sep 23 19:14:37 2012 WARNING: No server certificate verification method has been enabled. See http://openvpn.net/howto.html#mitm for more info. Sun Sep 23 19:14:37 2012 NOTE: OpenVPN 2.1 requires '--script-security 2' or higher to call user-defined scripts or executables Sun Sep 23 19:14:37 2012 LZO compression initialized Sun Sep 23 19:14:37 2012 Control Channel MTU parms [ L:1542 D:138 EF:38 EB:0 ET:0 EL:0 ] Sun Sep 23 19:14:38 2012 Data Channel MTU parms [ L:1542 D:1450 EF:42 EB:135 ET:0 EL:0 AF:3/1 ] Sun Sep 23 19:14:38 2012 Local Options hash (VER=V4): '41690919' Sun Sep 23 19:14:38 2012 Expected Remote Options hash (VER=V4): '530fdded' Sun Sep 23 19:14:38 2012 Socket Buffers: R=[163840-131072] S=[163840-131072] Sun Sep 23 19:14:38 2012 UDPv4 link local: [undef] Sun Sep 23 19:14:38 2012 UDPv4 link remote: [AF_INET]192.162.102.162:1194 Sun Sep 23 19:14:38 2012 TLS: Initial packet from [AF_INET]192.162.102.162:1194, sid=87a95723 a6d7b7f9 Sun Sep 23 19:14:38 2012 WARNING: this configuration may cache passwords in memory -- use the auth-nocache option to prevent this Sun Sep 23 19:14:38 2012 VERIFY OK: depth=1, /C=NV/ST=NV/L=nVPN/O=nVpn/CN=nVpn_CA/[email protected] Sun Sep 23 19:14:38 2012 VERIFY OK: depth=0, /C=NV/ST=NV/L=nVPN/O=nVpn/CN=server/[email protected] Sun Sep 23 19:14:39 2012 WARNING: 'link-mtu' is used inconsistently, local='link-mtu 1542', remote='link-mtu 6042' Sun Sep 23 19:14:39 2012 WARNING: 'tun-mtu' is used inconsistently, local='tun-mtu 1500', remote='tun-mtu 6000' Sun Sep 23 19:14:39 2012 Data Channel Encrypt: Cipher 'BF-CBC' initialized with 128 bit key Sun Sep 23 19:14:39 2012 Data Channel Encrypt: Using 160 bit message hash 'SHA1' for HMAC authentication Sun Sep 23 19:14:39 2012 Data Channel Decrypt: Cipher 'BF-CBC' initialized with 128 bit key Sun Sep 23 19:14:39 2012 Data Channel Decrypt: Using 160 bit message hash 'SHA1' for HMAC authentication Sun Sep 23 19:14:39 2012 Control Channel: TLSv1, cipher TLSv1/SSLv3 DHE-RSA-AES256-SHA, 1024 bit RSA Sun Sep 23 19:14:39 2012 [server] Peer Connection Initiated with [AF_INET]192.162.102.162:1194 Sun Sep 23 19:14:41 2012 SENT CONTROL [server]: 'PUSH_REQUEST' (status=1) Sun Sep 23 19:14:41 2012 PUSH: Received control message: 'PUSH_REPLY,redirect-gateway def1,dhcp-option DNS 8.8.8.8,dhcp-option DNS 8.8.8.8,route 10.102.162.1,topology net30,ping 10,ping-restart 120,ifconfig 10.102.162.6 10.102.162.5' Sun Sep 23 19:14:41 2012 OPTIONS IMPORT: timers and/or timeouts modified Sun Sep 23 19:14:41 2012 OPTIONS IMPORT: --ifconfig/up options modified Sun Sep 23 19:14:41 2012 OPTIONS IMPORT: route options modified Sun Sep 23 19:14:41 2012 OPTIONS IMPORT: --ip-win32 and/or --dhcp-option options modified Sun Sep 23 19:14:41 2012 ROUTE default_gateway=10.0.2.2 Sun Sep 23 19:14:41 2012 TUN/TAP device tun0 opened Sun Sep 23 19:14:41 2012 TUN/TAP TX queue length set to 100 Sun Sep 23 19:14:41 2012 /sbin/ifconfig tun0 10.102.162.6 pointopoint 10.102.162.5 mtu 1500 Sun Sep 23 19:14:41 2012 /sbin/route add -net 192.162.102.162 netmask 255.255.255.255 gw 10.0.2.2 Sun Sep 23 19:14:41 2012 /sbin/route add -net 0.0.0.0 netmask 128.0.0.0 gw 10.102.162.5 Sun Sep 23 19:14:41 2012 /sbin/route add -net 128.0.0.0 netmask 128.0.0.0 gw 10.102.162.5 Sun Sep 23 19:14:41 2012 /sbin/route add -net 10.102.162.1 netmask 255.255.255.255 gw 10.102.162.5 Sun Sep 23 19:14:41 2012 Initialization Sequence Completed

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  • Lockdown users on Windows Server 2012

    - by el.severo
    I set up a Active Directory on a server machine with Windows Server 2012 and I'd like to create some users with limitations like Windows Steady State does in Windows XP (locally). Seen already the Windows SteadyState Handbook (with Windows Server 2008), but I'd like to know if anyone has tried this before, the limitations are the following: 1. Prevent locked or roaming user profiles that cannot be found on the computer from logging on 2. Do not cache copies of locked or roaming user profiles for users who have previously logged on to this computer 3. Do not allow Windows to compute and store passwords using LAN Manager Hash values 4. Do not store usernames or passwords used to log on to the Windows Live ID or the domain 5. Prevent users from creating folders and files on drive C:\ 6. Lock profile to prevent the user from making permanent changes 7. Remove the Control Panel, Printer and Network Settings from the Classic Start menu 8. Remove the Favorites icon 9. Remove the My Network Places icon 10. Remove the Frequently Used Program list 11. Remove the Shared documents folder from My Computer 12. Remove control Panel icon 13. Remove the Set Program Access and Defaults icon 14. Remove the Network Connection(Connect To)icon 15. Remove the Printers and Faxes icon 16. Remove the Run icon 17. Prevent access to Windows Explorer features: Folder Options, Customize Toolbar, and the Notification Area 18. Prevent access to the taskbar 19. Prevent access to the command prompt 20. Prevent access to the registry editor 21. Prevent access to the Task Manager 22. Prevent access to Microsoft Management Console utilities 23. Prevent users from adding or removing printers 24. Prevent users from locking the computer 25. Prevent password changes (also requires the Control Panel icon to be removed) 26. Disable System Tools and other management programs 27. Prevent users from saving files to the desktop 28. Hide A Drive 29. Hide B Drive 30. Hide C Drive 31. Prevent changes to Internet Explorer registry settings 32. Empty the Temporary Internet Files folder when Internet Explorer is closed 33. Remove Internet Options 34. Remove General tab in Internet Options 35. Remove Security tab in Internet Options 36. Remove Privacy tab in Internet Options 37. Remove Content tab in Internet Options 38. Remove Connections tab in Internet Options 39. Remove Programs tab in Internet Options 40. Remove Advanced tab in Internet Options 41. Set a home page (Internet Explorer) 42. Restrict the possibility to change desktop image 43. Restrict the possibility to change wallpaper 44. Restrict usb flash drives Any suggestions for this? UPDATE: As @Dan suggested me I'd like to specify that would be applied to a educational scenario where students can login from a computer and want to add some restrictions to them.

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  • Need help modifying C++ application to accept continuous piped input in Linux

    - by GreeenGuru
    The goal is to mine packet headers for URLs visited using tcpdump. So far, I can save a packet header to a file using: tcpdump "dst port 80 and tcp[13] & 0x08 = 8" -A -s 300 | tee -a ./Desktop/packets.txt And I've written a program to parse through the header and extract the URL when given the following command: cat ~/Desktop/packets.txt | ./packet-parser.exe But what I want to be able to do is pipe tcpdump directly into my program, which will then log the data: tcpdump "dst port 80 and tcp[13] & 0x08 = 8" -A -s 300 | ./packet-parser.exe Here is the script as it is. The question is: how do I need to change it to support continuous input from tcpdump? #include <boost/regex.hpp> #include <fstream> #include <cstdio> // Needed to define ios::app #include <string> #include <iostream> int main() { // Make sure to open the file in append mode std::ofstream file_out("/var/local/GreeenLogger/url.log", std::ios::app); if (not file_out) std::perror("/var/local/GreeenLogger/url.log"); else { std::string text; // Get multiple lines of input -- raw std::getline(std::cin, text, '\0'); const boost::regex pattern("GET (\\S+) HTTP.*?[\\r\\n]+Host: (\\S+)"); boost::smatch match_object; bool match = boost::regex_search(text, match_object, pattern); if(match) { std::string output; output = match_object[2] + match_object[1]; file_out << output << '\n'; std::cout << output << std::endl; } file_out.close(); } } Thank you ahead of time for the help!

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  • Specializing a class template constructor

    - by SilverSun
    I'm messing around with template specialization and I ran into a problem with trying to specialize the constructor based on what policy is used. Here is the code I am trying to get to work. #include <cstdlib> #include <ctime> class DiePolicies { public: class RollOnConstruction { }; class CallMethod { }; }; #include <boost/static_assert.hpp> #include <boost/type_traits/is_same.hpp> template<unsigned sides = 6, typename RollPolicy = DiePolicies::RollOnConstruction> class Die { // policy type check BOOST_STATIC_ASSERT(( boost::is_same<RollPolicy, DiePolicies::RollOnConstruction>::value || boost::is_same<RollPolicy, DiePolicies::CallMethod>::value )); unsigned m_die; unsigned random() { return rand() % sides; } public: Die(); void roll() { m_die = random(); } operator unsigned () { return m_die + 1; } }; template<unsigned sides> Die<sides, DiePolicies::RollOnConstruction>::Die() : m_die(random()) { } template<unsigned sides> Die<sides, DiePolicies::CallMethod>::Die() : m_die(0) { } ...\main.cpp(29): error C3860: template argument list following class template name must list parameters in the order used in template parameter list ...\main.cpp(29): error C2976: 'Die' : too few template arguments ...\main.cpp(31): error C3860: template argument list following class template name must list parameters in the order used in template parameter list Those are the errors I get in Microsoft Visual Studio 2010. I'm thinking either I can't figure out the right syntax for the specialization, or maybe it isn't possible to do it this way.

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  • Detecting const-ness of nested type

    - by Channel72
    Normally, if I need to detect whether a type is const I just use boost::is_const. However, I ran into trouble when trying to detect the const-ness of a nested type. Consider the following traits template, which is specialized for const types: template <class T> struct traits { typedef T& reference; }; template <class T> struct traits<const T> { typedef T const& reference; }; The problem is that boost::is_const doesn't seem to detect that traits<const T>::reference is a const type. For example: std::cout << std::boolalpha; std::cout << boost::is_const<traits<int>::reference>::value << " "; std::cout << boost::is_const<traits<const int>::reference>::value << std::endl; This outputs: false false Why doesn't it output false true?

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  • What is the rationale to not allow overloading of C++ conversions operator with non-member function

    - by Vicente Botet Escriba
    C++0x has added explicit conversion operators, but they must always be defined as members of the Source class. The same applies to the assignment operator, it must be defined on the Target class. When the Source and Target classes of the needed conversion are independent of each other, neither the Source can define a conversion operator, neither the Target can define a constructor from a Source. Usually we get it by defining a specific function such as Target ConvertToTarget(Source& v); If C++0x allowed to overload conversion operator by non member functions we could for example define the conversion implicitly or explicitly between unrelated types. template < typename To, typename From > operator To(const From& val); For example we could specialize the conversion from chrono::time_point to posix_time::ptime as follows template < class Clock, class Duration> operator boost::posix_time::ptime( const boost::chrono::time_point<Clock, Duration>& from) { using namespace boost; typedef chrono::time_point<Clock, Duration> time_point_t; typedef chrono::nanoseconds duration_t; typedef duration_t::rep rep_t; rep_t d = chrono::duration_cast<duration_t>( from.time_since_epoch()).count(); rep_t sec = d/1000000000; rep_t nsec = d%1000000000; return posix_time::from_time_t(0)+ posix_time::seconds(static_cast<long>(sec))+ posix_time::nanoseconds(nsec); } And use the conversion as any other conversion. For a more complete description of the problem, see here or on my Boost.Conversion library.. So the question is: What is the rationale to non allow overloading of C++ conversions operator with non-member functions?

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  • Visual C++ 2010, rvalue reference bug?

    - by Sergey Shandar
    Is it a bug in Visual C++ 2010 or right behaviour? template<class T> T f(T const &r) { return r; } template<class T> T f(T &&r) { static_assert(false, "no way"); return r; } int main() { int y = 4; f(y); } I thought, the function f(T &&) should never be called but it's called with T = int &. The output: main.cpp(10): error C2338: no way main.cpp(17) : see reference to function template instantiation 'T f<int&>(T)' being compiled with [ T=int & ] Update 1 Do you know any C++x0 compiler as a reference? I've tried comeau online test-drive but could not compile r-value reference. Update 2 Workaround (using SFINAE): #include <boost/utility/enable_if.hpp> #include <boost/type_traits/is_reference.hpp> template<class T> T f(T &r) { return r; } template<class T> typename ::boost::disable_if< ::boost::is_reference<T>, T>::type f(T &&r) { static_assert(false, "no way"); return r; } int main() { int y = 4; f(y); // f(5); // generates "no way" error, as expected. }

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  • Should this work?

    - by Noah Roberts
    I am trying to specialize a metafunction upon a type that has a function pointer as one of its parameters. The code compiles just fine but it will simply not match the type. #include <iostream> #include <boost/mpl/bool.hpp> #include <boost/mpl/identity.hpp> template < typename CONT, typename NAME, typename TYPE, TYPE (CONT::*getter)() const, void (CONT::*setter)(TYPE const&) > struct metafield_fun {}; struct test_field {}; struct test { int testing() const { return 5; } void testing(int const&) {} }; template < typename T > struct field_writable : boost::mpl::identity<T> {}; template < typename CONT, typename NAME, typename TYPE, TYPE (CONT::*getter)() const > struct field_writable< metafield_fun<CONT,NAME,TYPE,getter,0> > : boost::mpl::false_ {}; typedef metafield_fun<test, test_field, int, &test::testing, 0> unwritable; int main() { std::cout << typeid(field_writable<unwritable>::type).name() << std::endl; std::cin.get(); } Output is always the type passed in, never bool_.

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