Add Libc.mkfifo

NEWS.md

@@ -111,6 +111,7 @@ New library functions
  provide one-argument method that returns a closure. The old methods of `merge` and
  `merge!` are still available for backward compatibility ([#34296]).
 * The new `isdisjoint` function indicates whether two collections are disjoint ([#34427]).
+* The new `Libc.mkfifo` function wraps `mkfifo` C function on Unix platforms ([#34587]).
 * Add function `ismutable` and deprecate `isimmutable` to check whether something is mutable.([#34652])
 * `include` now accepts an optional `mapexpr` first argument to transform the parsed
  expressions before they are evaluated ([#34595]).

base/libc.jl

@@ -10,6 +10,9 @@ import Core.Intrinsics: bitcast
 
 export FILE, TmStruct, strftime, strptime, getpid, gethostname, free, malloc, calloc, realloc,
  errno, strerror, flush_cstdio, systemsleep, time, transcode
+if Sys.isunix()
+ export mkfifo
+end
 if Sys.iswindows()
  export GetLastError, FormatMessage
 end
@@ -400,4 +403,27 @@ Interface to the C `srand(seed)` function.
 """
 srand(seed=floor(Int, time()) % Cuint) = ccall(:srand, Cvoid, (Cuint,), seed)
 
+"""
+ mkfifo(path::AbstractString, [mode::Integer]) -> path
+
+Make a FIFO special file (a named pipe) at `path`. Return `path` as-is on success.
+
+!!! compat "Julia 1.5"
+ `mkfifo` requires at least Julia 1.5.
+"""
+function mkfifo end
+
+if Sys.isunix()
+ function mkfifo(
+ path::AbstractString,
+ mode::Integer = Base.S_IRUSR | Base.S_IWUSR | Base.S_IRGRP | Base.S_IWGRP |
+ Base.S_IROTH | Base.S_IWOTH,
+ )
+ # Default `mode` is compatible with `mkfifo` CLI in coreutils.
+ ret = ccall(:mkfifo, Cint, (Cstring, Base.Cmode_t), path, mode)
+ systemerror("mkfifo", ret == -1)
+ return path
+ end
+end
+
 end # module

doc/src/base/libc.md

@@ -15,4 +15,5 @@ Base.Libc.strptime
 Base.Libc.TmStruct
 Base.Libc.flush_cstdio
 Base.Libc.systemsleep
+Base.Libc.mkfifo
 ```

test/file.jl

@@ -1510,3 +1510,20 @@ end
  end
  end
 end
+
+if Sys.isunix()
+ @testset "mkfifo" begin
+ mktempdir() do dir
+ path = Libc.mkfifo(joinpath(dir, "fifo"))
+ @sync begin
+ @async write(path, "hello")
+ cat_exec = `$(Base.julia_cmd()) --startup-file=no -e "write(stdout, read(ARGS[1]))"`
+ @test read(`$cat_exec $path`, String) == "hello"
+ end
+
+ existing_file = joinpath(dir, "existing")
+ write(existing_file, "")
+ @test_throws SystemError Libc.mkfifo(existing_file)
+ end
+ end
+end