stringByAppendingPathComponent, hows it work?

cocoa, objective-c

Solution

stringByAppendingPathComponent, hows it work?

Simple. You want to append a path component. You send that message to the string you want to append a path component to, passing the path component you want to append.

Path components are not the slashes; if they were, the `pathComponents` method would return nothing but an array of slashes. Path components are the parts between the slashes (although there is a special case, described in the definition of `pathComponents`).

The slash is the path separator. This is hard-coded inside of Cocoa; it's currently (and likely to always be) a slash. So, if you really wanted to append a slash to a string, the most likely reason would be that you want to append a path separator, not a path component.

    [newPath setString:rootPath];
    [newPath appendString:@"/"];
    [newPath appendString:fileName];

`fileName` is the component you want to add. Use `stringByAppendingPathComponent:` and pass `fileName`, not a slash.

As for whether your example leaks: Well, does an object fall out of scope without getting released? The answer to that question is the answer to whether it's a leak. If you're not sure, review the memory management rules.

Problem

EDIT_v002 I have had a look at all the comments and I am starting to see what I should be doing. To that end I have modified my code (see below) I have changed newPath to a NSString, removed the [[alloc] init] and the end [release] as its now handled by the system. I am using stringByAppendingPathComponent, letting it add a separator between rootPath and fileName before its assigned to the NSString. It does work, and I ran it through the static analyser with no problems. ``` // ------------------------------------------------------------------- ** // DISC: FILEWALKER ..... (cocoa_fileWalker.m) // DESC: List all "*.png" files in specified directory // ------------------------------------------------------------------- ** #import <Foundation/Foundation.h> int main (int argc, const char * argv[]) { NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; NSString *fileName; NSDictionary *attrDir; NSError *myError; NSNumber *fileSize; NSFileManager *manager = [NSFileManager defaultManager]; NSString *rootPath = [@"~/Pictures/Ren/PRMan" stringByExpandingTildeInPath]; NSString *newPath; NSLog(@"Home: %@",rootPath); for(fileName in [manager enumeratorAtPath:rootPath]){ if ([[fileName pathExtension] isEqual:@"png"]) { newPath = [rootPath stringByAppendingPathComponent:fileName]; attrDir = [manager attributesOfItemAtPath:newPath error:&myError]; fileSize = [attrDir objectForKey: @"NSFileSize"]; NSLog(@"File: %@ Size: %@", newPath, fileSize); } } [pool drain]; return 0; } // ------------------------------------------------------------------- ** ``` gary

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