tree 38a64aaefbdfc42063e6ade1fb2c4603bdeb1d0e
parent 8e0d832c7d84a3dd77f35828e1ff35045fc36fe7
author Bruce Merry <bmerry@gmail.com> 1494408984 +0200
committer Dean Moldovan <dean0x7d@gmail.com> 1494408984 +0200

Allow std::complex field with PYBIND11_NUMPY_DTYPE (#831)

This exposed a few underlying issues:

1. is_pod_struct was too strict to allow this. I've relaxed it to
require only trivially copyable and standard layout, rather than POD
(which additionally requires a trivial constructor, which std::complex
violates).

2. format_descriptor<std::complex<T>>::format() returned numpy format
strings instead of PEP3118 format strings, but register_dtype
feeds format codes of its fields to _dtype_from_pep3118. I've changed it
to return PEP3118 format codes. format_descriptor is a public type, so
this may be considered an incompatible change.

3. register_structured_dtype tried to be smart about whether to mark
fields as unaligned (with ^). However, it's examining the C++ alignment,
rather than what numpy (or possibly PEP3118) thinks the alignment should
be. For complex values those are different. I've made it mark all fields
as ^ unconditionally, which should always be safe even if they are
aligned, because we explicitly mark the padding.