if(png_ptr != NULL)  return((png_charp) PNG_HEADER_VERSION_STRING); return((png_charp) PNG_HEADER_VERSION_STRING);
if (&png_ptr != NULL)   return ((png_charp) PNG_HEADER_VERSION_STRING); return ((png_charp) "");
png_get_header_version(png_structp png_ptr){   /* Returns longer string containing both version and date */   if(png_ptr != NULL) /* silence compiler warning about unused png_ptr */      return((png_charp) PNG_HEADER_VERSION_STRING);   return((png_charp) PNG_HEADER_VERSION_STRING);}