Question

In OS X desktop application

NSFileManager *manager = [NSFileManager defaultManager];

NSDictionary *dirMeta = [NSDictionary dictionaryWithObjectsAndKeys:@"jack", @"creator", nil];
NSLog(@"%@", [dirMeta objectForKey:@"creator"]);//output jack

[manager createDirectoryAtPath:@"/Users/loki/Desktop/fromCap" withIntermediateDirectories:YES attributes:dirMeta error:NULL];

NSDictionary *attri2 = [manager attributesOfItemAtPath:@"/User/loki/Desktop/fromCap" error:nil];
NSLog(@"value is %@", [attri2 objectForKey:@"creator"]);//output null

Am I using createDirectoryAtPath wrongly?
Why attri2 get nothing data out of the directory?

Answer 1

The attributes dictionary is used to specify the filesystem attributes of the new directories/files:

attributes The file attributes for the new directory and any newly
created intermediate directories. You can set the owner and group
numbers, file permissions, and modification date. If you specify nil
for this parameter or omit a particular value, one or more default
values are used as described in the discussion. For a list of keys you
can include in this dictionary, see “Constants” section lists the
global constants used as keys in the attributes dictionary. Some of
the keys, such as NSFileHFSCreatorCode and NSFileHFSTypeCode, do not
apply to directories.

They are not for attaching arbitrary meta data. Where did you suppose this meta data would be stored anyway?