Add Libc.mkfifo

NEWS.md

@@ -29,6 +29,10 @@ Build system changes
 
 New library functions
 ---------------------
+
+* The new `Libc.mkfifo` function wraps the `mkfifo` C function on Unix platforms ([#34587]).
+* `hardlink(src, dst)` can be used to create hard links. ([#41639])
+* `diskstat(path=pwd())` can be used to return statistics about the disk. ([#42248])
 * `copyuntil(out, io, delim)` and `copyline(out, io)` copy data into an `out::IO` stream ([#48273]).
 
 New library features

base/libc.jl

@@ -12,7 +12,7 @@ import Core.Intrinsics: bitcast
 
 export FILE, TmStruct, strftime, strptime, getpid, gethostname, free, malloc, memcpy,
  memmove, memset, calloc, realloc, errno, strerror, flush_cstdio, systemsleep, time,
- transcode
+ transcode, mkfifo
 if Sys.iswindows()
  export GetLastError, FormatMessage
 end
@@ -437,6 +437,33 @@ function srand(seed::Integer=_make_uint64_seed())
  ccall(:jl_srand, Cvoid, (UInt64,), seed % UInt64)
 end
 
+"""
+ mkfifo(path::AbstractString, [mode::Integer]) -> path
+
+Make a FIFO special file (a named pipe) at `path`. Return `path` as-is on success.
+
+`mkfifo` is supported only in Unix platforms.
+
+!!! compat "Julia 1.8"
+ `mkfifo` requires at least Julia 1.8.
+"""
+function mkfifo(
+ path::AbstractString,
+ mode::Integer = Base.S_IRUSR | Base.S_IWUSR | Base.S_IRGRP | Base.S_IWGRP |
+ Base.S_IROTH | Base.S_IWOTH,
+)
+ @static if Sys.isunix()
+ # 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
+ else
+ # Using normal `error` because `systemerror("mkfifo", ENOTSUP)` does not
+ # seem to work on Windows.
+ error("mkfifo: Operation not supported")
+ end
+end
+
 struct Cpasswd
  username::Cstring
  uid::Culong

doc/src/base/libc.md

@@ -20,4 +20,5 @@ Base.Libc.TmStruct
 Base.Libc.FILE
 Base.Libc.flush_cstdio
 Base.Libc.systemsleep
+Base.Libc.mkfifo
 ```

test/file.jl

@@ -1636,6 +1636,28 @@ 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
+else
+ @test_throws(
+ "mkfifo: Operation not supported",
+ Libc.mkfifo(joinpath(pwd(), "dummy_path")),
+ )
+end
+
 @testset "chmod/isexecutable" begin
  mktempdir() do dir
  mkdir(joinpath(dir, "subdir"))