* Test dtype field order in numpy dtype tests
When running tests with NumPy 1.14 or later this test exposes the
"invalid buffer descriptor" error reported in #1274.
* Create dtype_ptr with ordered fields
* Fix casting of time points with non-system-clock duration on Windows
Add explicit `time_point_cast` to time point with duration of system
clock. Fixes Visual Studio compile error.
* Add test case for custom time points casting
In def_readonly and def_readwrite, there is an assertion that the member comes
from the class or a base class:
static_assert(std::is_base_of<C, type>::value, "...");
However, if C and type are the same type, is_base_of will still only be true
if they are the same _non-union_ type. This means we can't define accessors
for the members of a union type because of this assertion.
Update the assertion to test
std::is_same<C, type>::value || std::is_base_of<C, type>::value
which will allow union types, or members of base classes.
Also add a basic unit test for accessing unions.
* Fix async Python functors invoking from multiple C++ threads (#1587)
Ensure GIL is held during functor destruction.
* Add async Python callbacks test that runs in separate Python thread
In some cases the user of pythonbuf needs to allocate the internal
buffer to a specific size e.g. for performance or to enable synchronous
writes to the buffer.
By changing `pythonbuf::d_buffer` to be dynamically allocated we can now
enable these use-cases while still providing the default behavior of
allocating a 1024 byte internal buffer (through a default parameter).
I found that the numpy array tests already contained an empty-shaped
array test, but none with data in it.
Following PEP 3118, scalars have an empty shape and ndim 0. This
works already and is now also documented/covered by a test.
On some linuxes, /usr/include belongs to GCC and the standard
libraries that work with clang are in /usr/lib/clang/8.0.0 or
some variation thereof.
This results in errors such as:
```
/../lib64/gcc/x86_64-pc-linux-gnu/8.3.0/../../../../include/c++/8.3.0/bits/cxxabi_init_exception.h:38:10: fatal error: 'stddef.h' file not found
```
during extraction.
Bazel has a "strict" build model that requires all C++ header files be compilable on their own, and thus must explicitly #include all headers they require (even if de facto header inclusion order means they'd get them "for free"). This adds a couple of headers that are needed (but missing) by this model.
* Fixing order of arguments in call to PyErr_GivenExceptionMatches in pybind11::error_already_set.matches
* Added tests on error_already_set::matches fix for exception base classes
