cocoa NSFileManager wrong file size

Question

I'm using NSFileManager to get the size of some files in our application.

Each file is examined by a separate thread and the result for all the files is the same wrong value. The following code is ran for each file in a separate thread:

NSFileManager *fileManager= [[NSFileManager alloc] init];
NSUInteger completedFileSize = [[[fileManager attributesOfItemAtPath:fileName error:&error] objectForKey:NSFileSize] unsignedLongValue];
NSLog(@"Part %lu: %@ => size:%lu actual size:%lu", myPart.SequenceNumber, fileName, completedFileSize, myPart.Size);

The output is:

Part 1: /Users/David/TEMP/245E0BF53ECA/part1 => size:36864 actual size:37187

Part 5: /Users/David/TEMP/245E0BF53ECA/part5 => size:36864 actual size:37187

Part 2: /Users/David/TEMP/245E0BF53ECA/part2 => size:36864 actual size:37187

Part 4: /Users/David/TEMP/245E0BF53ECA/part4 => size:36864 actual size:37187

Part 3: /Users/David/TEMP/245E0BF53ECA/part3 => size:36864 actual size:37187

Part 6: /Users/David/TEMP/245E0BF53ECA/part6 => size:36864 actual size:37187

Part 7: /Users/David/TEMP/245E0BF53ECA/part7 => size:36864 actual size:37186

Part 0: /Users/David/TEMP/245E0BF53ECA/part0 => size:36864 actual size:37189

Also output of ls -l command on terminal is identical to the correct file sizes previously saved in myPart.Size

-rw-r--r-- 1 David staff 37189 Nov 25 11:25 part0

-rw-r--r-- 1 David staff 37187 Nov 25 11:25 part1

-rw-r--r-- 1 David staff 37187 Nov 25 11:25 part2

-rw-r--r-- 1 David staff 37187 Nov 25 11:25 part3

-rw-r--r-- 1 David staff 37187 Nov 25 11:25 part4

-rw-r--r-- 1 David staff 37187 Nov 25 11:25 part5

-rw-r--r-- 1 David staff 37187 Nov 25 11:25 part6

-rw-r--r-- 1 David staff 37186 Nov 25 11:25 part7

I'm using OS X 10.8 and Xcode 4.5.

Any help would be highly appreciated.

Answer 1

I Found the actual problem!

The file is not closed before the:

[[[fileManager attributesOfItemAtPath:fileName error:&error] objectForKey:NSFileSize] unsignedLongValue];

so I closed the file handler associated with fileName variable for path and the problem is solved.

fclose(myFile); //this is the handler for fileName
//now the value returned from the below line is correct.
[[[fileManager attributesOfItemAtPath:fileName error:&error] objectForKey:NSFileSize] unsignedLongValue];

Thanks from everyone.

Answer 2

我认为您应该使用defaultManager和fileSize来计算文件大小。

unsigned long long fileSize = [[[NSFileManager defaultManager] attributesOfItemAtPath:someFilePath error:nil] fileSize];