Vincent Gable’s Blog

May 6, 2008

Do Your Dishes In The Tub

Filed under: Tips
― Vincent Gable on May 6, 2008

Most bath faucets move significantly more gallons per minute then sink-faucets. So if you need to rinse something out quickly, do it in the tub. I’ve been using the tub/shower to rinse out large blender carafes for years, and it’s worth the walk to/from the bathroom, because of how much more quickly I can fill a 2L container. More water/second usually means more force. So if you don’t like wasting your time, rise your dishes in the tub.

May 4, 2008

Getting Mac OS X Version Information

Filed under: MacOSX,Objective-C,Programming,Sample Code,UNIX | , ,
― Vincent Gable on May 4, 2008

Cocoa

For a human-readable string, use [[NSProcessInfo processInfo] operatingSystemVersionString]. It looks like “Version 10.5 (Build 9A581)”, but that format might change in the future. NSProcessInfo.h explicitly warns against using it for parsing. It will always be human-readable though.

For machine-friendly numbers, use the Gestalt function, with one of the selectors:
gestaltSystemVersionMajor (in 10.4.17 this would be the decimal value 10)
gestaltSystemVersionMinor (in 10.4.17 this would be the decimal value 4)
gestaltSystemVersionBugFix (in 10.4.17 this would be the decimal value 17)
Do not use gestaltSystemVersion unless your code needs to run on OS X 10.2 or earlier. It’s a legacy function that can’t report minor/bugfix versions > 9; meaning it can’t distinguish between 10.4.9 and 10.4.11. The CocoaDev wiki has example code that works in 10.0 if you need to go that route.

Here’s a simpler example of using Gestalt:

- (BOOL) usingLeopard {
  long minorVersion, majorVersion;
  Gestalt(gestaltSystemVersionMajor, &majorVersion);
  Gestalt(gestaltSystemVersionMinor, &minorVersion);
  return majorVersion == 10 && minorVersion == 5;
}

Scripts

For scripts and command-line work, there is the sw_vers command.
$ sw_vers
ProductName: Mac OS X
ProductVersion: 10.5
BuildVersion: 9A581
$ sw_vers -productName
Mac OS X
$ sw_vers -productVersion
10.5
$ sw_vers -buildVersion
9A581

Java

Check the value of:

System.getProperty("os.name");
System.getProperty("os.version");

Fallback

Finally, if you must, you can parse /System/Library/CoreServices/SystemVersion.plist — but I don’t like the idea of doing that. There’s a chance that the file could have been corrupted or maliciously altered. It seems safer, and less complicated, to directly ask the operating system it’s version.

Minimum OS Requirements

To enforce a minimum OS requirement for your application, you can set the LSMinimumSystemVersion key in the Info.plist file. Big Nerd Ranch has a more robust, user-friendly, but complicated solution for older legacy systems.

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