Re: File path issue on Win32 only

[Richard Frith-Macdonald]

On 27 Feb 2007, at 11:34, Michael Hopkins wrote:

> Sorry to bug you directly but I believe you are the Windows guru  
> for GNUstep and we have a Windows-only question which has not yet  
> been answered on the public lists and which I think must have a  
> simple answer.

Sorry I didn't reply to your earlier messages ... I've been away at  
FOSDEM and rather busy (and mostly without the ability to send emails).

> In a Foundation tool, we initialise an object with a file in the  
> path where the executable resides:
>
>   [[Experiment alloc] initFromFile:@"test.gpe"];
>
>
> It uses this code internally:
>
>   -(Experiment *)        initFromFile:(NSString *) filePath
>   {
>     NSString*  file_off_disk = [NSString  
> stringWithContentsOfFile:filePath];

That all looks fine.
If the path is simply 'test.gpe' I'm surprised that anything could  
fail ... but I expect you already tried logging the value of filePath  
immediately before the call to stringWithContentsOfFile: to check  
that nothing has been done to modify the original path.


> This works fine on OS X and Linux, but gives the following error on  
> Win32:
>
>   2007-02-23 13:46:39.987 test.exe[1300] File NSData.m: 167. In  
> readContentsOfFile() attempt failed - The filename, directory name,  
> or volume label syntax is incorrect.

I don't think that particular error message exists in either the  
current release or in subversion trunk ... so my guess is that you  
are using an older version, so perhaps there is some old bug causing  
the trouble (though I can't remember anything likely).

I realise you may be using an older release of the software because  
no easy windows installer has been provided for the current  
release ... hopefully we can change that in a day or two (I've just  
been informed that a new installer is ready, so we just need to get  
it onto the server ready for download).

> Tried this as an attempted quick fix but it doesn't help:
>
>   [[Experiment alloc] initFromFile:[@"test.gpe"  
> stringByStandardizingPath]];
>
>
> Is there an object and/or method available in Foundation that lets  
> me easily convert local filenames to global ones in a form that all  
> platforms will understand?

The recommendation for portability is to only pass around relative  
paths, since absolute path names on windows and unix are  
incompatible.   You can use standard functions from NSPathUtilities.h  
and paths returned from NSBundle etc to find the base paths for your  
current platform, then use stringByAppendingPathComponent: to append  
the relative paths to those base paths.  That's really the only way  
to be sure that code which passes paths around is portable.