Add a second shared library in another directory

tests/packages/sharedlib-in-package/mypkg/__init__.py

@@ -7,12 +7,21 @@
 
 
 def _enable_sharedlib_loading():
-    """Ensure the `examplelib` shared library on Windows can be loaded
+    """
+    Ensure the `examplelib` and `examplelib2` shared libraries can be loaded on
+    Windows.
+
+    One shared library is installed alongside this __init__.py file. Windows can
+    load it because it searches for DLLs in the directory a .pyd (Python extension
+    module) is located in. Cygwin does not. For a shared library in another
+    directory inside the package, Windows also needs a hint.
+
+    This function is Windows-specific due to lack of RPATH support on Windows.
+    It cannot find shared libraries installed within wheels unless we either
+    amend the DLL search path or pre-load the DLL.
 
-    This shared library is installed alongside this __init__.py file. Due to
-    lack of RPATH support, Windows cannot find shared libraries installed
-    within wheels unless we either amend the DLL search path or pre-load the
-    DLL.
+    Note that `delvewheel` inserts a similar snippet into the main
+    `__init__.py` of a package when it vendors external shared libraries.
 
     .. note::
 
@@ -22,15 +31,18 @@ def _enable_sharedlib_loading():
         with `ctypes.WinDLL` may be preferred (the SciPy code base has an
         example of this).
     """
-    if os.name == "NOnt":
-        basedir = os.path.dirname(__file__)
-        os.add_dll_directory(basedir)
+    basedir = os.path.dirname(__file__)
+    subdir = os.path.join(basedir, 'sub')
+    if os.name == "nt":
+        os.add_dll_directory(subdir)
     elif sys.platform == "cygwin":
-        basedir = os.path.dirname(__file__)
-        os.environ["PATH"] = f"{os.environ['PATH']:s}:{basedir:s}"
+        os.environ["PATH"] = f"{os.environ['PATH']}:{basedir}:{subdir}"
 
 
 _enable_sharedlib_loading()
 
 
-from ._example import example_sum
+from ._example import example_prod, example_sum
+
+
+__all__ = ['example_prod', 'example_sum']

tests/packages/sharedlib-in-package/mypkg/_examplemod.c

@@ -5,6 +5,7 @@
 #include <Python.h>
 
 #include "examplelib.h"
+#include "examplelib2.h"
 
 static PyObject* example_sum(PyObject* self, PyObject *args)
 {
@@ -18,7 +19,20 @@ static PyObject* example_sum(PyObject* self, PyObject *args)
     return PyLong_FromLong(result);
 }
 
+static PyObject* example_prod(PyObject* self, PyObject *args)
+{
+    int a, b;
+    if (!PyArg_ParseTuple(args, "ii", &a, &b)) {
+        return NULL;
+    }
+
+    long result = prod(a, b);
+
+    return PyLong_FromLong(result);
+}
+
 static PyMethodDef methods[] = {
+    {"example_prod", (PyCFunction)example_prod, METH_VARARGS, NULL},
     {"example_sum", (PyCFunction)example_sum, METH_VARARGS, NULL},
     {NULL, NULL, 0, NULL},
 };

tests/packages/sharedlib-in-package/mypkg/examplelib.c

@@ -2,7 +2,7 @@
 //
 // SPDX-License-Identifier: MIT
 
-#include "mypkg_dll.h"
+#include "sub/mypkg_dll.h"
 
 MYPKG_DLL int sum(int a, int b) {
 	return a + b;

tests/packages/sharedlib-in-package/mypkg/examplelib.h

@@ -2,6 +2,6 @@
 //
 // SPDX-License-Identifier: MIT
 
-#include "mypkg_dll.h"
+#include "sub/mypkg_dll.h"
 
 MYPKG_DLL int sum(int a, int b);

tests/packages/sharedlib-in-package/mypkg/meson.build

@@ -23,10 +23,13 @@ example_lib_dep = declare_dependency(
   link_with: example_lib,
 )
 
+subdir('sub')
+
 py.extension_module(
     '_example',
     '_examplemod.c',
-    dependencies: example_lib_dep,
+    dependencies: [example_lib_dep, example_lib2_dep],
+    include_directories: 'sub',
     install: true,
     subdir: 'mypkg',
     install_rpath: '$ORIGIN',

tests/packages/sharedlib-in-package/mypkg/sub/examplelib2.c

@@ -0,0 +1,9 @@
+// SPDX-FileCopyrightText: 2022 The meson-python developers
+//
+// SPDX-License-Identifier: MIT
+
+#include "mypkg_dll.h"
+
+MYPKG_DLL int prod(int a, int b) {
+	return a * b;
+}

tests/packages/sharedlib-in-package/mypkg/sub/examplelib2.h

@@ -0,0 +1,7 @@
+// SPDX-FileCopyrightText: 2022 The meson-python developers
+//
+// SPDX-License-Identifier: MIT
+
+#include "mypkg_dll.h"
+
+MYPKG_DLL int prod(int a, int b);

tests/packages/sharedlib-in-package/mypkg/sub/meson.build

@@ -0,0 +1,16 @@
+# SPDX-FileCopyrightText: 2022 The meson-python developers
+#
+# SPDX-License-Identifier: MIT
+
+example_lib2 = shared_library(
+    'examplelib2',
+    'examplelib2.c',
+    c_args: export_dll_args,
+    install: true,
+    install_dir: py.get_install_dir() / 'mypkg/sub',
+)
+
+example_lib2_dep = declare_dependency(
+  compile_args: import_dll_args,
+  link_with: example_lib2,
+)

tests/test_wheel.py

@@ -166,6 +166,8 @@ def test_sharedlib_in_package(venv, wheel_sharedlib_in_package):
     venv.pip('install', wheel_sharedlib_in_package)
     output = venv.python('-c', 'import mypkg; print(mypkg.example_sum(2, 5))')
     assert int(output) == 7
+    output = venv.python('-c', 'import mypkg; print(mypkg.example_prod(6, 7))')
+    assert int(output) == 42
 
 
 @pytest.mark.skipif(MESON_VERSION < (1, 2, 3), reason='Meson version too old')