Couldn’t create window class error with a simple dialog-based Win32 application

I had a simple Win32 application fail to create its window (in my case, a dialog box, using either CreateDialog or DialogBox). I got back the error 0x583; unable to create window class. If I forced the window style on my dialog to create regardless of errors, my dialog was empty.

It turns out I was using themed controls in my manifest, but I didn’t call InitCommonControls. After that, my application worked.

There is no 64-bit type in C89

Brief post, but I was porting a C89 project to Visual C++ 6 (don’t ask) when I found something really fun. Turns out “long long“, the type everyone assumes is the 64-bit type in C, is actually a GCC extension. MSVC uses… _int64, a different extension. Great, had to convert a bunch of code. You’ll get this fun error from old MSVC when it sees it:

error C2632: 'long' followed by 'long' is illegal

(Note that MSVC will probably assume your C code is C++, which does mean you get some stuff from C99 for free like single-line comments… but then initializers are different between C and C++, and C++ only added long long in C++11…)

It’s an unfortunate gotcha for those who assume they’re writing standards compliant C89. The reason might be deflated when you have to define your own 64-bit integer with #ifdef. Oh, and let’s not forgot “long long” could mean 72-bit on your 9-bit byte system, of course. That’s why stdint.h exists…. except, oh, C89.

Loose ideas for operating systems

This post has been copy-edited by doppler. Thanks!

Most research nerds either start writing Unix hagiographies or start stapling a 99-point thesis at the doors of Murray Hill. This is the latter kind of post; I’ll try to cover ideas for systems that could be meaningfully different from current systems. I’ve done a lot of research on existing concepts and existing systems, particularly those that could have been the future. Existing systems can be extrapolated into something new.

A lot of the ideas have been percolating in my head for a while now and are rough ideas for what could be. Perhaps I’ll iterate on them further, or realize there’s a reason no one was doing these before. The main idea is a place to start off, and it iterates from there. Treat it like a buffet of ideas; caveat emptor for people who don’t like musing.

Continue reading