Hi there

I wonder if anyone could help me with the following C++ question: I've been given a custom-made string class which handles string, wstring and bstr. It has a number of methods and assignment operators to convert to and from different types.

The app I work on compiles happily in VS6 and VS2008, but when trying to compile in Redhat (version 4.1.1 in Redhat 5.0), for example for the following code:
MYString yyy = "abc";
std::string xxx1;
xxx1 = yyy; // THIS LINE GIVES AN ERROR
string zzz1 = yyy; // THIS LINE WORKS FINE

The error I get on the 3rd line is:

../../src/test.cpp:104: error: ambiguous overload for â?~operator=â?T in â?~xxx1 = yyyâ?T
/usr/lib/gcc/x86_64-redhat-linux/4.1.1/../../../../include/c++/4.1.1/bits/basic_string.h:485: note: candidates are: std::basic_string<_CharT, _Traits, _Alloc>& std::basic_string<_CharT, _Traits, _Alloc>:perator=(const std::basic_string<_CharT, _Traits, _Alloc>&) [with _CharT = char, _Traits = std::char_traits<char>, _Alloc = std::allocator<char>]
/usr/lib/gcc/x86_64-redhat-linux/4.1.1/../../../../include/c++/4.1.1/bits/basic_string.h:493: note: std::basic_string<_CharT, _Traits, _Alloc>& std::basic_string<_CharT, _Traits, _Alloc>:perator=(const _CharT*) [with _CharT = char, _Traits = std::char_traits<char>, _Alloc = std::allocator<char>] <near match>
/usr/lib/gcc/x86_64-redhat-linux/4.1.1/../../../../include/c++/4.1.1/bits/basic_string.h:504: note: std::basic_string<_CharT, _Traits, _Alloc>& std::basic_string<_CharT, _Traits, _Alloc>:perator=(_CharT) [with _CharT = char, _Traits = std::char_traits<char>, _Alloc = std::allocator<char>]
Any help would be greatly appreciated.

Cheers
JH7777

i dont like using the string class
i prefer char *
anyway i thinnk you need to add the class type to the class in order to have a sucessful assignment

You need to define a conversion operator
Although, I have to wonder *why* you want this custom string class. The generally accepted sane approach is to use a UTF-8 encoded std::string everywhere. It's understandable if you want to use std::wstring everywhere and do encoding/decoding into UTF-8 on I/O as well. Having multiple string encodings flying around is usually a recipe for disaster.

Thanks for the replies!!!

>> Although, I have to wonder *why* you want this custom string class.

Indeed a good question. I dislike custom string-classes, but have to support this for multi-platform / UTF-8 support (VS6, VS2008 and Unix)

>> You need to define a conversion operator
>> operator std::string() const;

Tried this, to no help ;(

I had operator
operator const string&() const;
already defined. I suspect that's why the following works:

MYString yyy = "abc";
std::string zzz1 = yyy; // THIS LINE WORKS FINE

And I don't understand why then the following doesn't work:

MYString yyy = "abc";
std::string xxx1;
xxx1 = yyy; // THIS LINE GIVES AN ERROR

Maybe one option would be to simply define
#define MYString std::string in g++
(if std::string supports UTF8 encoding in g++), but still the above error has me baffled.

Cheers
jh7777

Hmm. You're only allowed one compiler conversion and one user-defined conversion, but a conversion to const std::string & should do it. Do you also have a const char* conversion? If so, the two will conflict. It's strange that the copy constructor works.. they should either both work or neither work.

All versions of std::string support UTF-8 encoding. Well, not quite all.. If you have for some insane reason a really old 7-bit char computer this code needs to support. And by "really old", I mean like PDP-11 old.