gistfile1.txt

SInt32 TSSystemVersion(void) {
    
    static dispatch_once_t once;
    static int TSSystemVersionVal = 0x00;
    
    dispatch_once(&once, ^{
        NSDictionary *d = [NSDictionary dictionaryWithContentsOfFile:@"/System/Library/CoreServices/SystemVersion.plist"];
        
        NSString *prodVersion = [d objectForKey:@"ProductVersion"];
        
        // sanity.
        FMAssert([prodVersion isKindOfClass:[NSString class]]);
        
        if ([[prodVersion componentsSeparatedByString:@"."] count] < 3) {
            prodVersion = [prodVersion stringByAppendingString:@".0"];
        }
        
        FMAssert([[prodVersion componentsSeparatedByString:@"."] count] == 3);
        
        NSString *junk = [prodVersion stringByReplacingOccurrencesOfString:@"." withString:@""];
        
        
        char *e = nil;
        TSSystemVersionVal = (int) strtoul([junk UTF8String], &e, 16);
        
    });
    
    return TSSystemVersionVal;
    
    
    //The above replaces this:
    
    /*
    SInt32 v;
    Gestalt(gestaltSystemVersion, &v);
    return v;
    */
}


if ((TSSystemVersion() >= 0x10100)) {
  …
}