Mac Forum / Programming / Mac Programming / February 2008

For the life of me I can't see why the following code hangs in
fprintf():

- (bool) matchesPattern: (NSString *) file
{
    unsigned int npatterns = [skipPatterns_ count];
    unsigned int i;
    for ( i = 0; i < npatterns; i ++ )
    {
        const char * pattern = [[skipPatterns_ objectAtIndex: i]
cStringUsingEncoding: NSASCIIStringEncoding];
        if ( ! pattern )
            return FALSE;
        // convert file name to c string, making sure it is plain ascii
        NSData * fn_data =  [file dataUsingEncoding: NSASCIIStringEncoding
allowLossyConversion: YES];
        char fn_buf[1000];
        unsigned int len = [fn_data length];
        len = (len < 999) ? len : 999;
        [fn_data getBytes: fn_buf length: len];
        fn_buf[len] = 0;
fprintf(stderr, fn_buf );
        if ( fnmatch( pattern, fn_buf, 0 /*FNM_LEADING_DIR*/ ) == 0 )
        {
            // NSLog(@"match %s - %@", pattern, file );
            return TRUE;
        }
    }
    return FALSE;
}

The function matchesPattern gets called many times without problems
(apparently).
And when it hangs in fprintf(), I can look at fn_buf in the debugger
and it is a well-formed C-string ...

Does anyone have any idea, why this might occasionally hang? Or what I
can try?

All hints and suggestions will be appreciated.

Best regards,
Gabriel.