Make import_numpy a function

Author: SylvainCorlay

docs/source/basic_usage.rst

@@ -29,7 +29,7 @@ Example 1: Use an algorithm of the C++ library on a numpy array inplace
 
     PYBIND11_PLUGIN(xtensor_python_test)
     {
-        import_numpy(); //this is actually a macro
+        xt::import_numpy();
         pybind11::module m("xtensor_python_test", "Test module for xtensor python bindings");
 
         m.def("sum_of_sines", sum_of_sines,
@@ -80,7 +80,7 @@ Example 2: Create a universal function from a C++ scalar function
 
     PYBIND11_PLUGIN(xtensor_python_test)
     {
-        import_numpy();
+        xt::import_numpy();
         py::module m("xtensor_python_test", "Test module for xtensor python bindings");
 
         m.def("vectorized_func", xt::pyvectorize(scalar_func), "");

docs/source/numpy_capi.rst

@@ -17,7 +17,7 @@ When writing an extension module that is self-contained in a single file, its au
 points:
 
 - ``FORCE_IMPORT_ARRAY`` must be defined before including any header of ``xtensor-python``.
-- ``import_numpy()`` must be called in the function initializing the module.
+- ``xt::import_numpy()`` must be called in the function initializing the module.
 
 Thus the basic skeleton of the module looks like:
 
@@ -29,7 +29,7 @@ Thus the basic skeleton of the module looks like:
 
     PYBIND11_PLUGIN(plugin_name)
     {
-        import_numpy();
+        xt::import_numpy();
         pybind11::module m(//...
         //...
         return m.ptr();

include/xtensor-python/pycontainer.hpp

@@ -19,6 +19,7 @@
 
 #ifndef FORCE_IMPORT_ARRAY
 #define NO_IMPORT_ARRAY
+static int _import_array() { return 0; };
 #endif
 #ifndef PY_ARRAY_UNIQUE_SYMBOL
 #define PY_ARRAY_UNIQUE_SYMBOL xtensor_python_ARRAY_API
@@ -29,11 +30,21 @@
 
 #include "xtensor/xcontainer.hpp"
 
-#define import_numpy() { if (_import_array() < 0) {PyErr_Print(); PyErr_SetString(PyExc_ImportError, "numpy.core.multiarray failed to import"); } }
-
 namespace xt
 {
 
+    /**
+     * Import the numpy Python module.
+     */
+    inline void import_numpy()
+    {
+        if (_import_array() < 0)
+        {
+            PyErr_Print();
+            PyErr_SetString(PyExc_ImportError, "numpy.core.multiarray failed to import");
+        }
+    }
+
     /**
      * @class pycontainer
      * @brief Base class for xtensor containers wrapping numpy arryays.

test/main.cpp

@@ -20,7 +20,7 @@ int main(int argc, char* argv[])
 {
     // Initialize all the things (google-test and Python interpreter)
     Py_Initialize();
-    import_numpy();
+    xt::import_numpy();
     ::testing::InitGoogleTest(&argc, argv);
 
     // Run test suite

test_python/main.cpp

@@ -51,7 +51,7 @@ int add(int i, int j)
 
 PYBIND11_PLUGIN(xtensor_python_test)
 {
-    import_numpy();
+    xt::import_numpy();
 
     py::module m("xtensor_python_test", "Test module for xtensor python bindings");