Question

Will it get over written or will write fail?

NSData * pdfData = [[NSData alloc] initWithData:[PDFImageConverter convertImageToPDF: [image image]]];
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString * filename = sharedManager.localFileName; //file name already exists
    NSString *pdfPath = [documentsDirectory stringByAppendingPathComponent:filename];
    [pdfData writeToFile:pdfPath atomically:YES];
    [pdfData release];

Answer 1

It will get overwritten if writing succeeds. Note that if atomically is set to YES, the original file won’t get damaged if writing fails. If atomically is set to NO, it will.