Add NullRequest type

examples/juliac/Makefile

@@ -0,0 +1,27 @@
+JULIA ?= $(shell which julia)
+JULIAC ?= $(shell $(JULIA) -e 'print(normpath(joinpath(Sys.BINDIR, Base.DATAROOTDIR, "julia", "juliac.jl")))')
+
+RUNIC_FILES := $(wildcard ../src/*.jl) ../Project.toml
+
+runicc: runicc.jl Project.toml Manifest.toml $(RUNIC_FILES) check-julia
+	$(JULIA) --project=. $(JULIAC) --verbose --output-exe $@ --experimental --trim=unsafe $<
+
+Manifest.toml: Project.toml ../Project.toml
+	$(JULIA) --project=. -e 'using Pkg; Pkg.instantiate()'
+	@touch $@ # Pkg.instantiate doesn't update the mtime if there are no changes
+
+clean:
+	-rm -f runicc Manifest.toml
+
+check-julia:
+	@if ! $(JULIA) --help-hidden | grep -s -q '\-\-trim'; then \
+		echo "ERROR: The configured julia binary ($(JULIA)) does not support the --trim argument."; \
+		echo "       Configure the binary using the JULIA variable (e.g. \`JULIA=/path/to/julia make ...\`)"; \
+		echo "       or change how \`julia\` resolves in \`PATH\`."; \
+		exit 1; \
+	fi
+
+print-%:
+	@echo '$*=$($*)'
+
+.PHONY: clean check-julia

examples/juliac/Project.toml

@@ -0,0 +1,5 @@
+[deps]
+MPI = "da04e1cc-30fd-572f-bb4f-1f8673147195"
+
+[sources]
+MPI = {path = "../.."}

examples/juliac/main.jl

@@ -0,0 +1,19 @@
+module MPIC
+
+# Compileable main function corresponding to `int main(int argc, char** argv)`
+Base.@ccallable function main(argc::Cint, argv::Ptr{Ptr{UInt8}})::Cint
+    # Load command line arguments. Note that the first argument is the
+    # executable name so we skip it.
+    args = Vector{String}(undef, argc - 1)
+    for i in 2:argc
+        argptr = unsafe_load(argv, i)
+        arg = unsafe_string(argptr)
+        args[i - 1] = arg
+    end
+    return 0
+end
+
+# Tell juliac about the main entrypoint
+Base.Experimental.entrypoint(main, (Cint, Ptr{Ptr{UInt8}}))
+
+end

src/nonblocking.jl

@@ -190,8 +190,17 @@ Base.unsafe_convert(::Type{MPI_Request}, request::Request) = request.val
 Base.unsafe_convert(::Type{Ptr{MPI_Request}}, request::Request) = convert(Ptr{MPI_Request}, pointer_from_objref(request))
 
 
-const REQUEST_NULL = Request(API.MPI_REQUEST_NULL[], nothing)
-add_load_time_hook!(LoadTimeHookSetVal(REQUEST_NULL, API.MPI_REQUEST_NULL))
+struct NullRequest <: AbstractRequest end
+const REQUEST_NULL = NullRequest()
+
+Base.convert(::Type{Request}, ::NullRequest) =
+    Request(API.MPI_REQUEST_NULL[], nothing)
+
+isnull(::NullRequest) = true
+setbuffer!(::NullRequest, ::Any) = throw(ArgumentError("Cannot set buffer on NullRequest"))
+
+# const REQUEST_NULL = Request(API.MPI_REQUEST_NULL[], nothing)
+# add_load_time_hook!(LoadTimeHookSetVal(REQUEST_NULL, API.MPI_REQUEST_NULL))
 
 """
     MPI.UnsafeRequest()