function NetSend(Dest, Source, Msg: string): Longint;
  type
TNetMessageBufferSendFunction = function(servername,
                                           msgname,
                                           fromname: PWideChar;
                                           buf: PWideChar;
                                           buflen: Cardinal): Longint; stdcall;
var
NetMessageBufferSend: TNetMessageBufferSendFunction;
SourceWideChar: PWideChar;
DestWideChar: PWideChar;
MessagetextWideChar: PWideChar;
Handle: THandle;
begin
Handle := LoadLibrary('NETAPI32.DLL');
if Handle = 0 then
begin
Result := GetLastError;
Exit;
end;
@NetMessageBufferSend := GetProcAddress(Handle, 'NetMessageBufferSend');
if @NetMessageBufferSend = nil then
begin
Result := GetLastError;
Exit;
end;
MessagetextWideChar := nil;
try
GetMem(MessagetextWideChar, Length(Msg) * SizeOf(WideChar) + 1);
GetMem(DestWideChar, 20 * SizeOf(WideChar) + 1);
StringToWideChar(Msg, MessagetextWideChar, Length(Msg) * SizeOf(WideChar) + 1);
StringToWideChar(Dest, DestWideChar, 20 * SizeOf(WideChar) + 1);
if Source = '' then
Result := NetMessageBufferSend(nil, DestWideChar, nil,
MessagetextWideChar, Length(Msg) * SizeOf(WideChar) + 1)
else
begin
GetMem(SourceWideChar, 20 * SizeOf(WideChar) + 1);
StringToWideChar(Source, SourceWideChar, 20 * SizeOf(WideChar) + 1);
Result := NetMessageBufferSend(nil, DestWideChar, SourceWideChar,
MessagetextWideChar, Length(Msg) * SizeOf(WideChar) + 1);
FreeMem(SourceWideChar);
end;
finally
FreeMem(MessagetextWideChar);
FreeLibrary(Handle);
end;
end;