How to set volume name when converting MacOSPath to POSIX

Question

In a Carbon app I need to convert an HFS style MacOS path into a POSIX one that can be used in an fopen() call. For example:

my Vol:myFolder:myFile.jpg

to something like:

/my Vol/myFolder/myFile.jpg

If my Vol is my sytem disk, /myFolder/myFile.jpg works just fine, but if it's on a different volume, it does not work (ie. my Vol/myFolder/myFile.jpg fails.

How to I specify the volume here?

Thanks!

Bill

I'm not sure if I edited this right, because the example is inconsistent about whether the path separator is a colon or a slash, so I don't know if it's supposed to be an HFS path. — JWWalker
– JWWalker, Commented Jul 21, 2012 at 2:09
@JonathanGrynspan: Yes, and kCFURLHFSPathStyle still refers to a colon-delimited path. — JWWalker
– JWWalker, Commented Aug 6, 2012 at 16:22

Jonathan Grynspan · Accepted Answer · 2012-08-06 16:39:08Z

2

An approach that avoids hard-coding (consider a volume not mounted in /Volumes/, such as a manually mounted one.)

CFStringRef myHFSPath = CFSTR("Macintosh HD:Some Folder:Some Subfolder:Some File");

CFURLRef url = CFURLCreateWithFileSystemPath(NULL, myHFSPath, kCFURLHFSPathStyle, FALSE);
if (url) {
    UInt8 posixPath[PATH_MAX * 2]; /* Extra-large because why not? */
    if (CFURLGetFileSystemRepresentation(url, TRUE, posixPath, sizeof(posixPath)) {
        /*
            posixPath now contains a C string suitable for passing to BSD and
            C functions like fopen().
        */
    }
    CFRelease(url);
}

edited Aug 6, 2012 at 16:39

answered Aug 5, 2012 at 1:27

Jonathan Grynspan

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Comments

torrey.lyons · Accepted Answer · 2012-07-20 22:38:45Z

0

For POSIX style paths you need to preface secondary volumes with "/Volumes". So your example would be, /Volumes/myVol/myFolder/myFile.jpg. Note even if myVol is your system disk this works. So prefacing with /Volumes is always safe.

answered Jul 20, 2012 at 22:38

torrey.lyons

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1 Comment

Jonathan Grynspan Over a year ago

Eeeeh! This is hard-coding and subject to failure in the future or on a non-standard system configuration.

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