Storage B

(via OpenDDS)

• Java Bindings for OpenDDS
• Added the ability for using multiple repositories to provide redundant service metadata management
• Implemented the WaitSet, GuardCondition, and StatusCondition interfaces from the OMG DDS specification
• Implemented DomainParticipant::get_current_time() from formal/07-01-01
• Removed requirement for repository domain specification files
• Internal service Entity identifiers have been expanded to 128 bits
• dcps_ts.pl changes
• DCPSInfoRepo changes
• Fixed bug in DCPSInfoRepo that did not re-evaluate the compatibility and associations when QoS change is made
• Fixed bugs that affected connection establishment
• Added datalink_release_delay and removed keep_link configuration
• Fixed a potential deadlock in reliable multicast transport

See the Release Notes for details.

(via OpenDDS)

• More QoS features have been implemented
• dispose() notifications have been added
• Added IPv6 support
• Improved memory management
• Multicast transport improvements
• Implemented Changeable QoS policies
• Use multiple DCPSInfoRepos
• Documentation updates
• New tests and examples

See the Release Notes for details.

Back when I was developing shiphandling simulator software, I ran into situations where it was necessary to convert decimal degrees to degrees, minutes, and seconds (for example, nautical types like to express latitude/longitude using degrees, minutes, and seconds while computers prefer decimal degrees).

Here's some C++ functions which handle the conversion between these two formats:

std::string DMS::DegreesMinutesSeconds(double ang,
                                       unsigned int num_dec_places = 2)
std::string DMS::DegreesMinutesSecondsLat(double ang,
                                          unsigned int num_dec_places = 2)
std::string DMS::DegreesMinutesSecondsLon(double ang,
                                          unsigned int num_dec_places = 2)

double DMS::DecimalDegrees(const std::string& dms)

These are inline functions defined in the header file, dms.h:

Here’s some C++ functions which evaluate Chebyshev polynomials:

T₀(x):
double T0(double x) ;

T₁(x):
double T1(double x) ;

T₂(x):
double T2(double x) ;

T_n(x):
double Tn(unsigned int n, double x) ;

These are inline functions defined in the header file, chebyshev.h:

OpenDDS:

OpenDDS is an open source C++ implementation of the Object Management Group (OMG) Data Distribution Service (DDS). OpenDDS leverages the Adaptive Communication Environment (ACE) to provide a cross platform environment.

OpenDDS is supported by Object Computing, Inc.

Download OpenDDS here.

• X Windows Programming in C++: Part I
• X Windows Programming in C++: Part II

Continuing with our task of creating a C++ version of basicwin.c, we next look at XCreateSimpleWindow. Here’s some code snippets from basicwin.c showing the use of XCreateSimpleWindow:

• X Windows Programming in C++: Part I

Continuing with our task of creating a C++ version of basicwin.c, we next look at XOpenDisplay / XCloseDisplay. Here’s some code snippets from basicwin.c showing the use of these functions:

Years ago, I did quite a bit X Windows programming. When I started developing X Windows software, I was also learning C++ (this was a long time ago). Unfortunately , the X Windows system I was developing software for did not have a C++ compiler. This led to some frustration since using C++ would have made some of my tasks easier.

A fews years later, I worked on another project using X and Motif. It was mandated that this software be written in C leading to same frustration I experience when I first started learning X (by this time I was a seasoned C++ developer, so writing anything in C seemed like a step backward).

I’ve decided to revisit X Windows programming on my own for a few reasons:

• I’m a little rusty when it comes to X Windows programming.
  
  
• I want to use X in a project I’ve been contemplating for the past few years.
  
  
• I’m currently working on Microsoft Windows C++/C# project at work and I want to do some non-Microsoft programming on my own.

My first step in getting back into X Windows programming was to revist the book, Xlib Programming Manual, Rel. 5. The examples in this book are written in C (Kerninghan and Ritchie C, no less). One of these examples, basicwin.c, demonstrates the fundementals of programming with the X library. I figure coming up with a C++ version of basicwin.c would be a useful learning experience for myself and possibly others.

I’ll start out by taking pieces of basicwin.c and converting them to C++. I’ll start with following code fragments showing the use of the structures: XSizeHints, XWMHints, and XClassHint.

Here’s some C++ functions which evaluate Legendre polynomials:

P₀(x):
double P0(double x) ;

P₁(x):
double P1(double x) ;

P₂(x):
double P2(double x) ;

P_n(x):
double Pn(unsigned int n, double x) ;

These are inline functions defined in the header file, legendre.h:

Here’s some code stolen from The Daily WTF:

ushort GetAsciiValue (uchar ch)
{
    ushort i;
    for (i=0; i<=255; i++)
    {
        if(ch == i)
            return i;
    }
    return 0;
}

It might be interesting to show this code to a candidate for a C/C++ position. Ask him/her if there is anything wrong with this code, and if so, how he/she would implement GetAsciiValue.