Add copyright notice

NOTICE

@@ -0,0 +1,51 @@
+                            User Rights Notice
+
+This software and related material (data and (or) documentation),
+contained in or furnished in connection with PHREEQC, are made available
+by the U.S. Geological Survey (USGS) to be used in the public interest
+and in the advancement of science.  You may, without any fee or cost,
+use, copy, modify, or distribute this software, and any derivative works
+thereof, and its supporting documentation, subject to the following
+restrictions and understandings.
+
+If you distribute copies or modifications of the software and related
+material, make sure the recipients receive a copy of this notice and
+receive or can get a copy of the original distribution.  If the software
+and (or) related material are modified and distributed, it must be
+made clear that the recipients do not have the original and they must
+be informed of the extent of the modifications.  For example, modified
+files must include a prominent notice stating the modifications made, the
+author of the modifications, and the date the modifications were made.
+This restriction is necessary to guard against problems introduced in the
+software by others, reflecting negatively on the reputation of the USGS.
+
+The software is public property and you therefore have the right to
+the source code, if desired.
+
+You may charge fees for distribution, warranties, and services provided
+in connection with the software or derivative works thereof.  The name
+USGS can be used in any advertising or publicity to endorse or promote
+any products or commercial entity using this software if specific
+written permission is obtained from the USGS.
+
+The user agrees to appropriately acknowledge the authors and the USGS
+in publications that result from the use of this software or in products
+that include this software in whole or in part.
+
+Although this software program has been used by the U.S. Geological
+Survey (USGS), no warranty, expressed or implied, is made by the USGS
+or the U.S. Government as to the accuracy and functioning of the
+program and related program material nor shall the fact of distribution
+constitute any such warranty, and no responsibility is assumed by the
+USGS in connection therewith. 
+
+The authors, the USGS, and the United States Government are not
+obligated to provide the user with any support, consulting, training or
+assistance of any kind with regard to the use, operation, and
+performance of this software nor to provide the user with any updates,
+revisions, new versions, or "bug fixes."
+
+The user assumes all risk for any damages whatsoever resulting from
+loss of use, data, or profits arising in connection with the access,
+use, quality, or performance of this software.
+

README.md

@@ -2,8 +2,6 @@
 
 Python bindings of [PHREEQC Version 3](https://www.usgs.gov/software/phreeqc-version-3)
 
-The original C/C++ source code was downloaded from [IPhreeqc Modules](https://water.usgs.gov/water-resources/software/PHREEQC/iphreeqc-3.7.3-15968.tar.gz) made by USGS.
-
 ## Install
 ```
 pip install phreeqc
@@ -12,10 +10,13 @@ pip install phreeqc
 ```py
 from phreeqc import Phreeqc
 
-
 p = Phreeqc()
-p.load_database("phreeqc.dat")
-p.run_string(
+error_count = p.load_database("phreeqc.dat")
+
+if error_count != 0:
+    raise RuntimeError("Failed to load database")
+
+error_count = p.run_string(
     """
 TITLE Example 2.--Temperature dependence of solubility
                   of gypsum and anhydrite
@@ -46,6 +47,18 @@ END
 """
 )
 
+if error_count != 0:
+    raise RuntimeError("Failed to run string")
+
 selected_output = p.get_selected_output()
+
 print(selected_output)
+
 ```
+## License
+This project provides Python bindings for the iphreeqc software. The bindings are distributed under the [MIT License](/LICENSE), which applies to the Python and C++ binding code in this repository.
+
+However, please note:
+
+IPHREEQC, the underlying software to which these bindings provide access, is made available by the U.S. Geological Survey (USGS) under the terms described in its [User Rights Notice](/NOTICE). You can also find the full text of the license in the iphreeqc source or documentation.
+By using this project, you agree to comply with the terms outlined in the iphreeqc license as well as the MIT license for the Python bindings.

src/main.cpp

@@ -10,14 +10,26 @@ namespace py = pybind11;
 class _Phreeqc : public IPhreeqc
 {
 public:
-    void _AccumulateLine(const char *line)
+    bool _AccumulateLine(const char *line)
     {
         auto result = AccumulateLine(line);
         if (result == VR_OUTOFMEMORY)
         {
-            throw std::runtime_error("Failure, Out of memory");
+            return false;
         }
+        return true;
     }
+
+    bool _SetCurrentSelectedOutputUserNumber(int n)
+    {
+        auto result = SetCurrentSelectedOutputUserNumber(n);
+        if (result == VR_INVALIDARG)
+        {
+            return false;
+        }
+        return true;
+    }
+
     const std::variant<long, double, std::string> _GetSelectedOutputValue(int row, int col)
     {
 
@@ -135,7 +147,7 @@ PYBIND11_MODULE(_iphreeqc, m)
         .def("run_accumulated", &_Phreeqc::RunAccumulated)
         .def("run_file", &_Phreeqc::RunFile)
         .def("run_string", &_Phreeqc::RunString)
-        .def("set_current_selected_output_user_number", &_Phreeqc::SetCurrentSelectedOutputUserNumber)
+        .def("set_current_selected_output_user_number", &_Phreeqc::_SetCurrentSelectedOutputUserNumber)
         .def("set_dump_file_name", &_Phreeqc::SetDumpFileName)
         .def("set_dump_file_on", &_Phreeqc::SetDumpFileOn)
         .def("set_dump_string_on", &_Phreeqc::SetDumpStringOn)
@@ -153,5 +165,5 @@ PYBIND11_MODULE(_iphreeqc, m)
         .def("set_selected_output_file_on", &_Phreeqc::SetSelectedOutputFileOn)
         .def("set_selected_output_string_on", &_Phreeqc::SetSelectedOutputStringOn);
 
-    m.attr("__version__") = "0.1.2";
+    m.attr("__version__") = "0.2.0";
 }