I’ve been wanting to rewrite one of my VB.Net programs over in C++ recently, just to force myself to learn the language better. Since there was no way in hell I was going to tackle any program with a graphical user interface, I chose the locking portion of my Multi-Monitor Cursor Lock to port. Looking over the code for a recent feature-request update, it seemed like most of the code involved Windows API function calls and data types, which are actually easier to implement than in VB (you just have to include windows.h).
Really, the two most difficult to learn fundamentals of C (having come from a VB/Java/PHP background) are character strings and pointers. Pointers really aren’t that bad once you learn how the operators work, but you still have to stop and think about any redirections: “& returns an address, * returns a value”. The problem with strings is that there are a million types of them and getting them to play nice requires all sorts of tricks; there’s character arrays, pointers to characters, constant version of both of those (which I still don’t really get–how can something return a constant?), string class, cstring class, wide characters, ANSI characters, Unicode characters, multi-byte characters. Since I wasn’t using MFC or ATL, I decided to stick with the string class, which could be initialized from character arrays or character pointers. And although its
c_str() function returns a
const char *, you can use
strcpy() to easily get a
char *, which many API functions require.
After trudging through the code for parsing the command line switches in and reading default values, the code for the actual locking portion just kind of rolled out (being comprised almost completely of API calls). Doing the code was fun, but the benefits that I
saw during performance testing blew me away. I ran the VB.Net and C++ versions for two minutes at 20ms poll rate to see the CPU usage. .Net used 8.6 seconds of CPU time compared to C++’s .3 seconds: a 29 times performance increase! This test couldn’t have been more definitive as the algorithms were virtually the same; remember, I said the locking portion was mostly system calls. Then, I tested memory efficiency, which was also delightful but the difference was less dramatic: ~16,000KB to ~1,500KB (~10x less memory) or ~7,000KB to ~400KB (~17x less) using the
SetProcessWorkingSetSize(hProc, -1, -1) trick–not too shabby. Also, without the .Net “Just-in-Time” compiling, the C++ version doesn’t have a two to three second start and close delay.
Happy with my results, I started working on new documentation for Cursor Lock 2.0, so I could submit to some download sites. It was about complete when I decided to turn in for the night on Saturday. As I laid in bed, nearly asleep, I heard the fans in my computer spinning down, the silence cutting through my subconscious. Peering over at the tower, I noticed the power light still on, which was even odder than the system randomly powering down. I went over and tried to restart, but it wouldn’t stay on long enough to even begin to POST and blue smoke smell had already permeated the room. The next morning, I smelled around the tower and found the culprit to be the power supply, as I suspected. After taking the PSU apart and dissecting it on the kitchen table, I found an interestingly charred transformer coil. When I plugged the PSU in and shorted the power-on pin, a spark leapt from aforementioned transformer to a plastic insulation divider. Upon further inspection, it appeared the divider had actually melted to the transformer.
Obviously, this power supply was dead beyond anything I could repair, so I ordered a new 500W Thermaltake PSU from Newegg. I tried to get one that I could still use whenever I finally get to upgrade my core system components; the key to this was in the 20+4-pin ATX main connector that allows you to break the newest 4 pins away from it. In retrospect, I had probably been overloading the old PSU for a while now, which was leading to some system instabilities when gaming. It was rated for 350W, but most wattage calculations I had done put my usage at slightly above that. Anyways, here’s some pics of the new power supply. I should have gotten one with it inside the case, but oh well…some other time.
Luckily, after that disaster, none of my other hardware had been fried (from an over-voltage or such), and I got to finish the documentation and polish of the new Cursor Lock. I submitted it to a few download sites, but it could be weeks before they get approved. What independent developer has $1000 for their premium services? Not to mention that there are thousand of good download sites on the web. Well, until it appears on other sites, the new version can be found right where it always was here.