Dtrebbien's List: Programming

• Often you will receive data in a non-spatial form such as comma delimited data with latitude and longitude fields. To take full advantage of PostGIS spatial abilities, you will want to create geometry fields in your new table and update that field using the longitude latitude fields you have available.
• To create the Geometry field, use the AddGeometryColumn opengis function.
• The above code will create a geometry column named thepoint_longlat in the table zctas that validates to make sure the inputs are 2-dimensional points in SRID 4269 (NAD83 longlat).
• In the code below, we will create a new geometry field that holds points in the WGS 84 North Meter reference system and then updates that field accordingly.

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• why NIO is really not the best way anymore (post linux 2.6 kernel and NPTL) and multithreaded I/O is the new old-way of doing things.

• This article lists the CFLAGS settings considered "safe" for a given processor. These are the settings you should use if you are unsure what CFLAGS your processor needs.
• This page is for those who don't want to experiment, and want a stable system, but still optimized for their CPU. But remember, by using these flags, binaries from your system might not work on another one with a different CPU.
• GCC 4.2 introduces a new -march option, -march=native, which automatically detects the features your CPU supports and sets the options appropriately.

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• Porting Windows applications to Linux doesn't have to involve a  retraining nightmare. Markus Neifer shows how to port MFC using wxWindows,  giving a user's guide to this open source GUI toolkit and providing a  complete, step-by-step porting example.

• What does PERMIS do for you?

    
   
  •  It helps to control access to your computer resources
    
  •  When users request access to your resources, PERMIS makes the access control decisions for you based on your access control policies and the roles of the users
    
  •  It uses only your policies, and makes sure they have not been tampered with first
    
  •  It allows you to delegate to trusted individuals the ability to assign roles to users on your behalf
    
  •  It makes sure that the trusted individuals do not exceed their delegated authority
    
  •  It supports dynamic delegation of authority, which allows any user with a role to delegate it to other users in the same group

• CHP is a Haskell library featuring a concurrency model inspired by CSP (Communicating Sequential Processes, hence the name), and all its various renderings in occam-pi, JCSP, C++CSP2, etc. The concurrency is built around encapsulated processes, without any shared data, that interact via barriers and one-way typed synchronous channels.

• C++CSP2 is a library that provides easy mechanisms for concurrent C++ programming. The CSP-derived approach is to eliminate sharing of data between concurrent processes. Processes are separate pieces of code that communicate explicitly via channels. When programming a process, you only need to consider the channel communications (and other synchronisations, such as barriers), and do not need to worry about race hazards involving shared data or scheduling corner-cases.

• If you have a user enter data in your Web app using combining characters, and then another does a search with canonical characters, the search will fail. This won’t do at all.

    

  The solution is to normalize your Unicode data. In Perl, you can use the Unicode::Normalize, a C/XS module that uses Perl’s internal unicode tables to convert things as appropriate. For general use the NFC normalization is probably best:

    

  use Unicode::Normalize; $string = NFC $string; 

   

  PostgreSQL offers no normalization routines. However, the SQL standard mandates one (as of SQL 2008, at least).
• we can use PL/PerlU to emulate it in PostgreSQL