gethostname

// WS2_32.dll
#include <windows.h>

INT gethostname(
    LPSTR name,
    INT namelen
);

<DllImport("WS2_32.dll", SetLastError:=True, ExactSpelling:=True)>
Public Shared Function gethostname(
    <MarshalAs(UnmanagedType.LPStr)> name As System.Text.StringBuilder,   ' LPSTR out
    namelen As Integer   ' INT
) As Integer
End Function

' name : LPSTR out
' namelen : INT
Declare PtrSafe Function gethostname Lib "ws2_32" ( _
    ByVal name As String, _
    ByVal namelen As Long) As Long
' VBA7前提(PtrSafe)。32bit Office では LongPtr→Long。Integer=16bit / Long=32bit / LongLong=64bit。

import ctypes
from ctypes import wintypes

gethostname = ctypes.windll.ws2_32.gethostname
gethostname.restype = ctypes.c_int
gethostname.argtypes = [
    wintypes.LPSTR,  # name : LPSTR out
    ctypes.c_int,  # namelen : INT
]
# GetLastError: use ctypes.GetLastError() (or ctypes.WinDLL(use_last_error=True))

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('WS2_32.dll')
gethostname = Fiddle::Function.new(
  lib['gethostname'],
  [
    Fiddle::TYPE_VOIDP,  # name : LPSTR out
    Fiddle::TYPE_INT,  # namelen : INT
  ],
  Fiddle::TYPE_INT)

#[link(name = "ws2_32")]
extern "system" {
    fn gethostname(
        name: *mut u8,  // LPSTR out
        namelen: i32  // INT
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("WS2_32.dll", SetLastError = true)]
public static extern int gethostname([MarshalAs(UnmanagedType.LPStr)] System.Text.StringBuilder name, int namelen);
"@
$api = Add-Type -MemberDefinition $sig -Name 'WS2_32_gethostname' -Namespace Win32 -PassThru
# $api::gethostname(name, namelen)

#uselib "WS2_32.dll"
#func global gethostname "gethostname" sptr, sptr
; gethostname varptr(name), namelen   ; 戻り値は stat
; name : LPSTR out -> "sptr"
; namelen : INT -> "sptr"
; ※HSP3.7は #func のため戻り値はシステム変数 stat に格納されます。

#uselib "WS2_32.dll"
#cfunc global gethostname "gethostname" var, int
; res = gethostname(name, namelen)
; name : LPSTR out -> "var"
; namelen : INT -> "int"
; ※出力/バッファ引数は var 方式(変数を直接渡す)。varptr 方式にも切替可。

; INT gethostname(LPSTR name, INT namelen)
#uselib "WS2_32.dll"
#cfunc global gethostname "gethostname" var, int
; res = gethostname(name, namelen)
; name : LPSTR out -> "var"
; namelen : INT -> "int"
; ※出力/バッファ引数は var 方式(変数を直接渡す)。varptr 方式にも切替可。

import (
	"golang.org/x/sys/windows"
	"unsafe"
)

var (
	ws2_32 = windows.NewLazySystemDLL("WS2_32.dll")
	procgethostname = ws2_32.NewProc("gethostname")
)

// name (LPSTR out), namelen (INT)
r1, _, err := procgethostname.Call(
	uintptr(name),
	uintptr(namelen),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // INT

function gethostname(
  name: PAnsiChar;   // LPSTR out
  namelen: Integer   // INT
): Integer; stdcall;
  external 'WS2_32.dll' name 'gethostname';

result := DllCall("WS2_32\gethostname"
    , "Ptr", name   ; LPSTR out
    , "Int", namelen   ; INT
    , "Int")   ; return: INT

●gethostname(name, namelen) = DLL("WS2_32.dll", "int gethostname(char*, int)")
# 呼び出し: gethostname(name, namelen)
# name : LPSTR out -> "char*"
# namelen : INT -> "int"
# なでしこ1は32bit・ANSI(Shift_JIS)。文字列=char*(ANSI)、ポインタ/ハンドル=void*(4byte)。