如何将unicode字符串从C ++传递到delphi？

Question

Ive found many topics about passing from Delphi to C++ but still confused about.

std::string s1(" look 👆 here ");

What is the correct way to pass it to a delphi code?

none of this is not working, producing wrong chars

char * s = (char *)s1.c_str();
Call_Delphi_func(s);
.......
Memo1.Lines.Add(UTF8String(PChar(pointer(s))));

Answer 1

You did not say which version of Delphi you are using, but the fact that you use UTF8String the way you are implies that you are using Delphi 2009 or later. If so, PChar is PWideChar ( wchar_t* in C and C++). Use PAnsiChar ( char* in C and C++) explicitly instead, and get rid of your unnecessary Pointer typecast:

std::string s1 = u8" look 👆 here ";
char * s = const_cast<char*>(s1.c_str());
Delphi_func(s);

procedure Delphi_func(s: PAnsiChar); stdcall;
begin
  Memo1.Lines.Add(UTF8String(s));
end;

Alternatively, use std::wstring with PWideChar instead:

std::wstring s1 = L" look 👆 here ";
wchar_t * s = const_cast<wchar_t*>(s1.c_str());
Delphi_func(s);

procedure Delphi_func(s: PWideChar); stdcall;
begin
  Memo1.Lines.Add(s);
end;