c++ - Exporting template code = dangerous? (MSVC) -

-

As I have written in another question, I came across this issue when I came to 1.40 through MSVC 7 And raised many C24251 warnings.

Now, after reading the article, I wonder: Is it generally frustrating to export the template code, such as 

  class DLLEXPORT_MACRO AClass {public: Std :: vector & lt; Int & gt; GetVecCopy () {myVec; } ...}

This code has been compiled into a DLL through MSVC7.1. Although this code does not cause any errors referenced from another MSVC7.1 code, it is said that the MSVC8 code in this DLL correlates to runtime (memory alignment issues?). .

Because it is clearly bad ... What is a "best practice" to deal with the issue of exporting template code?

This is a bad idea, as the std :: vector is different or there is a difference between the compiler versions Could. However, this could possibly fail in load times, since the name of std :: vector should be different in compatible compiler versions (this name is part of the argument for mangling).

This link-time failure is something that can not actually be implemented as a developer, though in addition to purchasing a compiler supporting it. The second solution is to keep the template type completely out of the DLL interface. Keep them in private members.

Note that the problem is not unique to templates for a moment, imagine that std :: string is UDT instead of typing, and the compiler is provided by runtime . It can still change between compiler versions and of course between compiler vendors. It will still be unusable in a DLL interface.

For these reasons, Practical Solutions 0. Use C, 1. Use COM or 2. Arrange on a compiler version.


Comments

Post a Comment

Popular posts from this blog

MySql variables and php -

-
I am getting an error with php in order to format mysql_query () in php to format this string What is the right way? SELECT SELECT SELECT (*) Agents @AgentCount; User_Agent_English, User_Angent_Oursal, US.___Gent_Aginal, COUNT (User_Agent_Percade) ACC, COUNT (*) / (AgentCount) Percentage by agents user_agent_preser order DEC limit limit 50; In PHP, how am i setting $ query $ query = "SELECT count (*) agents @ agentcount; SELECT user_agent_parsed, User_agent_original , COUNT (user_agent_parsed) ascount, COUNT (*) / (@AgentCount) as a percentage by user_agent_parced by URI date DESC limit 50 "; This exact query will work properly if I put it in MySQL directly through a command line session. Do I need to release two separate php calls from mysql_query () and store the results first? I get the following error: There is an error in your SQL syntax; Instead of using a sub-selection and instead of using the 'SELECT user_agent_parsed, user_agent_original, ne...
Read more

url rewriting - How to implement the returnurl like SO in PHP? -

-
This URL should work even after the rewrite. Is this possible? Otherwise, I can only hardcoded everything If you are trying to create a login system with redirection You need to use the HTTP_REFERER header to find out where the user came from so that you can send it back there. The best way to do this is to use something like this in your login form: // - Login php & Lt; Input type = "password" name = "password" /> & Lt; Input type = "hidden" name = "returnrelale" value = "& lt ;? php echo $ redirectURL ;? & gt;" / & Gt; & Lt; / Form & gt; Please note that some ISP, browser or proxy will delete the referrer header, so you can not rely on each user to work fully. If you use a statement, to check whether the header exists or not, you can send those users back to the homepage or whatever. Edit If you are looking to use $ _SERVER ['REQUEST_URI'], if you are running Apache It sho...
Read more

Which Python client library should I use for CouchdB? -

-
I am starting to experiment with CouchDB because it looks like we have the right solution to certain problems That all the work will be on a new project, which does not have any legacy dependency, which the client library will suggest you use, and why? If we overlap any of the OS. Freeband is available only in the collection of its ports, but asks to use the library's project website. None of those people are Ubuntu, which is only with ships, since those two OSAs are not common in libraries, I am probably installing something from source (and hopefully if I have time, then Ubuntu and FreeBSD People pack the package). For those interests, I want to use CouchDB as a convenient intermediate storage space for data passed between different services - think of a message bus system, but less formalities with. For example, we have daemons that download and pars the web page, then send an interesting bit to other daemons for further processing. Many of them are ill-defined until the...
Read more