[Diff since v0.19.1](JuliaParallel/MPI.jl@v0.19.1...v0.19.2)

**Closed issues:**
- Support the MPI Group interface (JuliaParallel#277)
- Default and/or keyword args (JuliaParallel#423)
- Don't redefine `MPI_UNDEFINED` to 0 (JuliaParallel#499)
- Deadlock with MPI.jl + OpenMPI on a cluster (JuliaParallel#517)
- MPI.jl + PackageCompiler (JuliaParallel#518)

**Merged pull requests:**
- Add methods for keyword integer arguments (JuliaParallel#510) (@simonbyrne)
- add citation (JuliaParallel#516) (@simonbyrne)
- Various fixes to documentation (JuliaParallel#520) (@giordano)
- Add group functions (v2.0) (JuliaParallel#521) (@carlocastoldi)

[Diff since v0.19.0](JuliaParallel/MPI.jl@v0.19.0...v0.19.1)

**Closed issues:**
- Is that possible to send/receive a number instead of array? (JuliaParallel#308)
- MPI_Gather (JuliaParallel#348)
- gethostbyname error on macos 10.15 (github actions vm) (JuliaParallel#407)
- Homebrew MPICH giving incorrect result on MPI.File.get_position_shared (JuliaParallel#413)
- mpirun instead of mpiexecjl works fine as well (JuliaParallel#448)
- Use with Extrae (JuliaParallel#454)
- Using Arrow.Table with MPI.jl (JuliaParallel#461)
- Accessing underlying MPI_Comm from CxxWrap (JuliaParallel#487)
- building MPI.jl fails (JuliaParallel#488)
- Error installing against system MPI (JuliaParallel#489)
- `show` on an MPI Datatype can fail if MPI is not initialized. (JuliaParallel#490)
-  Install MPI.jl on HPC (JuliaParallel#505)

**Merged pull requests:**
- simplify test/wait (JuliaParallel#479) (@simonbyrne)
- Make `show` on Datatype functional before MPI has been initialized (JuliaParallel#491) (@simonbyrne)
- Add comment to top of auto-generated deps.jl file (JuliaParallel#493) (@eschnett)
- fix Scatterv! function signature in docstring (JuliaParallel#494) (@carstenbauer)
- Fix typo in create_resized (JuliaParallel#495) (@carstenbauer)
- update one sided API (JuliaParallel#496) (@simonbyrne)
- fix runtests (JuliaParallel#507) (@simonbyrne)
- fix SentinelPtr conversion error (JuliaParallel#509) (@simonbyrne)
- Fix job schedule example in documentation (JuliaParallel#511) (@giordano)
- Added interface to MPI Ibarrier collective (JuliaParallel#512) (@mikegros)

## MPI v0.19.0

[Diff since v0.18.2](JuliaParallel/MPI.jl@v0.18.2...v0.19.0)


**Closed issues:**
- More user-friendly MPI.Init (JuliaParallel#484)

**Merged pull requests:**
- Remove MacOS workarounds (JuliaParallel#477) (@simonbyrne)
- add nice init function (JuliaParallel#485) (@simonbyrne)

add nice init function (JuliaParallel#485)

* add nice init function

* make multiple Finalize safe

* bump version

* add error if trying to initialize after finalize

## MPI v0.18.2

[Diff since v0.18.1](JuliaParallel/MPI.jl@v0.18.1...v0.18.2)


**Closed issues:**
- mpiexecjl test fails when it can't find julia on the path (JuliaParallel#476)
- Error in Irecv! due to missing `strides` method (JuliaParallel#478)

**Merged pull requests:**
- Remove `Pkg` from test environment (JuliaParallel#480) (@giordano)
- [mpiexecjl] Accept `JULIA_BINDIR` as environment variable (JuliaParallel#481) (@giordano)
- use unsafe_convert instead of cconvert to ensure handles aren't GCed during ccall (JuliaParallel#482) (@simonbyrne)

## MPI v0.18.1

[Diff since v0.18.0](JuliaParallel/MPI.jl@v0.18.0...v0.18.1)



**Merged pull requests:**
- Run CI on aarch64 with Drone (JuliaParallel#472) (@giordano)
- Throw an error when using custom reductions on non-Intel platforms (JuliaParallel#473) (@giordano)
- Add a bunch of barriers to io_shared tests (JuliaParallel#474) (@simonbyrne)
- Update TagBot setup and reduce frequency of CompatHelper to once per day (JuliaParallel#475) (@giordano)

[Diff since v0.17.2](JuliaParallel/MPI.jl@v0.17.2...v0.18.0)

**Closed issues:**
- Count arguments of `Scatterv` etc. should be `Int`, not `Cint` (JuliaParallel#153)
- MPI.Gatherv! should only require counts for root (JuliaParallel#362)
- `MPI.Datatype()` creates new instance on every `MPI.Put()` (JuliaParallel#462)
- An example that uses `Scatterv` (JuliaParallel#468)
- An example on how to `Scatterv!` and `Gatherv!` a two-dimensional array? (JuliaParallel#469)

**Merged pull requests:**
- add basic error handler functionality (JuliaParallel#457) (@simonbyrne)
- use Buffers with one-sided ops (JuliaParallel#464) (@simonbyrne)
- Fix one-argument in-place `Alltoall!` (JuliaParallel#465) (@mtsch)
- docstrings for one-sided operations (JuliaParallel#466) (@joachimbrand)
- loosen type restrictions on one-sided buffers (JuliaParallel#467) (@simonbyrne)
- Add Scatterv example based on JuliaParallel#469 (JuliaParallel#470) (@simonbyrne)
- Improve Datatype handling (JuliaParallel#471) (@simonbyrne)

[Diff since v0.17.1](JuliaParallel/MPI.jl@v0.17.1...v0.17.2)

**Closed issues:**
- Sending and receiving custom types causes memory leaks (JuliaParallel#459)

**Merged pull requests:**
- Add finalizer to `create_struct` (JuliaParallel#460) (@mtsch)

[Diff since v0.17.0](JuliaParallel/MPI.jl@v0.17.0...v0.17.1)

**Closed issues:**
- MPI tracing and profiling (JuliaParallel#444)
- Support for error handlers (JuliaParallel#453)
- InitError on Julia 1.3 with system MPI (JuliaParallel#455)

**Merged pull requests:**
- Avoid InitError on Julia 1.3 with system MPI libraries (JuliaParallel#456) (@jipolanco)
- Allow `Waitall!` for an empty input `reqs = []` (JuliaParallel#458) (@ali-ramadhan)

[Diff since v0.16.1](JuliaParallel/MPI.jl@v0.16.1...v0.17.0)

**Closed issues:**
- Code question - why do you use @view? (JuliaParallel#445)

**Merged pull requests:**
- Allow libmpi.so to be in lib64 (JuliaParallel#441) (@calebwin)
- remove references to deprecated collectives (JuliaParallel#442) (@simonbyrne)
- Remove unnecessary views (JuliaParallel#446) (@simonbyrne)
- Add new example to docs (JuliaParallel#449) (@rafabench)
- use global symbols on Unix to support LD_PRELOAD interception (JuliaParallel#451) (@simonbyrne)