Compilation issue with HDF5 1.12.1

[ax3l]

Describe the bug
With conda-forge migrating over to HDF5 1.12.1, I see compilation issues with ADIOS2, v2.7.1.

To Reproduce
conda-forge/adios2-feedstock#33

Expected behavior
Should compile.

Desktop (please complete the following information):

• OS/Platform: Microsoft Windows Server 2016, 10.0.14393, Datacenter
• Build: MSVC 19.16.27045.0, build type: shared

Additional context
Error message:

%SRC_DIR%\source\adios2\engine\mixer\HDFMixerWriter.cpp(96): warning C4267: 'initializing': conversion from 'size_t' to 'int', possible loss of data
%SRC_DIR%\source\adios2\engine\mixer\HDFMixerWriter.cpp(123): error C2131: expression did not evaluate to a constant
%SRC_DIR%\source\adios2\engine\mixer\HDFMixerWriter.cpp(123): note: failure was caused by a read of a variable outside its lifetime
%SRC_DIR%\source\adios2\engine\mixer\HDFMixerWriter.cpp(123): note: see usage of 'this'
%SRC_DIR%\source\adios2\engine\mixer\HDFMixerWriter.cpp(124): error C2131: expression did not evaluate to a constant
%SRC_DIR%\source\adios2\engine\mixer\HDFMixerWriter.cpp(124): note: failure was caused by a read of a variable outside its lifetime
%SRC_DIR%\source\adios2\engine\mixer\HDFMixerWriter.cpp(124): note: see usage of 'this'
%SRC_DIR%\source\adios2\engine\mixer\HDFMixerWriter.cpp(131): error C2672: 'adios2::helper::Comm::Gather': no matching overloaded function found

cc @guj @pnorbert

[ax3l]

Line 123/124: Variable lengths arrays are not C++:

ADIOS2/source/adios2/engine/mixer/HDFMixerWriter.cpp

Lines 122 to 124 in 94c2e37

	/* Initialize hyperslab values. */
	size_t all_starts[m_NumSubFiles][nDims];
	size_t all_counts[m_NumSubFiles][nDims];

needs new, a unique ptr or a std::vector

[ax3l]

Comm::Gather()

ADIOS2/source/adios2/engine/mixer/HDFMixerWriter.cpp

Line 131 in 94c2e37

m_SubfileComm.Gather(start.data(), nDims, all_starts[0], nDims, 0);

vs.

ADIOS2/source/adios2/helper/adiosComm.h

Lines 218 to 221 in 94c2e37

	template <typename TSend, typename TRecv>
	void Gather(const TSend *sendbuf, size_t sendcount, TRecv *recvbuf,
	size_t recvcount, int root,
	const std::string &hint = std::string()) const;

I guess here is the case that hsize_t is not the same as size_t on all platforms, since both types are platform dependent.

[ax3l]

Discussed with @guj on Slack: HDF5Mixer is an experiment, so both disabling the code or fixing the small issues above is fine for us.

[ax3l]

Pushed a potential approach to fix this in #2864

Will check if this fixes it in conda-forge/adios2-feedstock#33

[ax3l]

Removed component: #2866

[ax3l]

After removing HDFMixer, I see more Windows build issues for ADIOS 2.7.1 when upgrading from HDF5 1.10.6 to 1.12.1 in conda-forge/adios2-feedstock#37 with H5VolUtil @guj @pnorbert:

d:\bld\adios2_1635999120575\work\source\h5vol\H5VolUtil.h(136): error C2146: syntax error: missing ')' before identifier 'ndims'
d:\bld\adios2_1635999120575\work\source\h5vol\H5VolUtil.h(136): error C2081: 'uint': name in formal parameter list illegal
d:\bld\adios2_1635999120575\work\source\h5vol\H5VolUtil.h(136): error C2061: syntax error: identifier 'ndims'
d:\bld\adios2_1635999120575\work\source\h5vol\H5VolUtil.h(136): error C2059: syntax error: ';'
d:\bld\adios2_1635999120575\work\source\h5vol\H5VolUtil.h(136): error C2059: syntax error: ')'
d:\bld\adios2_1635999120575\work\source\h5vol\H5VolUtil.h(137): error C2449: found '{' at file scope (missing function header?)
d:\bld\adios2_1635999120575\work\source\h5vol\H5VolUtil.h(143): error C2059: syntax error: '}'
d:\bld\adios2_1635999120575\work\source\h5vol\H5VolUtil.h(166): warning C4244: 'return': conversion from 'hsize_t' to 'int', possible loss of data
d:\bld\adios2_1635999120575\work\source\h5vol\H5VolUtil.h(169): error C2057: expected constant expression
d:\bld\adios2_1635999120575\work\source\h5vol\H5VolUtil.h(169): error C2466: cannot allocate an array of constant size 0
d:\bld\adios2_1635999120575\work\source\h5vol\H5VolUtil.h(169): error C2133: 's': unknown size
d:\bld\adios2_1635999120575\work\source\h5vol\H5VolUtil.h(169): error C2133: 'e': unknown size
d:\bld\adios2_1635999120575\work\source\h5vol\H5VolUtil.h(183): warning C4244: 'return': conversion from 'hsize_t' to 'int', possible loss of data
%SRC_DIR%\source\h5vol\H5VolReadWrite.c(19): fatal error C1083: Cannot open include file: 'unistd.h': No such file or directory

Is there a patch I can try for this? I see you already did some updates to this since the last release.

[guj]

wc H5VolUtil.h
47 133 1187 H5VolUtil.h

why is yours showing more than 100 lines?

• Junmin

[ax3l]

Because I build the latest stable release, ADIOS 2.7.1. @guj
conda-forge/adios2-feedstock#37