PRFileDesc *top;
PRFileDesc *top, *lower; PRStatus rv;
static PRStatus PR_CALLBACK pl_TopClose (PRFileDesc *fd){    PRFileDesc *top;    PR_ASSERT(fd != NULL);    PR_ASSERT(fd->lower != NULL);    PR_ASSERT(fd->secret == NULL);    PR_ASSERT(fd->methods->file_type == PR_DESC_LAYERED);    if (fd->higher != NULL)    {        PR_SetError(PR_BAD_DESCRIPTOR_ERROR, 0);        return PR_FAILURE;    }    top = PR_PopIOLayer(fd, PR_TOP_IO_LAYER);    top->dtor(top);    return (fd->methods->close)(fd);}