Fix fifo length (issue #66)

Jan Breuer

2016-02-14 fbd16b32739a35ed3d3cf7e9aa4cfb6a75758e46

 libscpi/src/expression.c

@@ -245,6 +245,8 @@
            *dimensions = fromDimensions;
            return SCPI_EXPR_OK;
        }
    } else if (err == SCPI_EXPR_NO_MORE) {
        err = SCPI_EXPR_ERROR;
    }

    return err;