Migrating from VC++ 6.0 to VC++ 2005

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Arjun - 24 May 2007 20:37 GMT

Hi,

After migrating my application from VC++ 6.0 to VC++ 2005, I receive the
error C2593 'operator +=' is ambiguous.

It refers to the following line:

Name += pManager->GetAgentName();

where Name is a string and GetAgentName also returns a string.

Please suggest.

Regards,
Arjun

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Nathan Mates - 24 May 2007 21:25 GMT

>After migrating my application from VC++ 6.0 to VC++ 2005, I receive the
>error C2593 'operator +=' is ambiguous.

>Name += pManager->GetAgentName();
>where Name is a string and GetAgentName also returns a string.

The concept of 'string' in C++ is a very vague and overloaded
concept. Do you mean a char*, a std::string, a CString (ATL/MFC), a
tstring? [Or any other number of custom C++ string classes which may
exist in your code.] Or the unicode versions of any/all of those?

My recommendation: find out what the types *really* are in the line
you posted above. That'll usually help point you in the right
direction, as I bet you'll find that they're different.

Nathan Mates
--
<*> Nathan Mates - personal webpage http://www.visi.com/~nathan/
# Programmer at Pandemic Studios -- http://www.pandemicstudios.com/
# NOT speaking for Pandemic Studios. "Care not what the neighbors
# think. What are the facts, and to how many decimal places?" -R.A. Heinlein

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Arjun - 24 May 2007 22:01 GMT

HI Nathan,

Its a CString.

CString MachineName;

Regards,
Arjun

> >After migrating my application from VC++ 6.0 to VC++ 2005, I receive the
> >error C2593 'operator +=' is ambiguous.
[quoted text clipped - 17 lines]
> # NOT speaking for Pandemic Studios. "Care not what the neighbors
> # think. What are the facts, and to how many decimal places?" -R.A. Heinlein

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Nathan Mates - 24 May 2007 22:28 GMT

>> >After migrating my application from VC++ 6.0 to VC++ 2005, I receive the
>> >error C2593 'operator +=' is ambiguous.

>> >Name += pManager->GetAgentName();
>> >where Name is a string and GetAgentName also returns a string.

>> The concept of 'string' in C++ is a very vague and overloaded
>> concept. Do you mean a char*, a std::string, a CString (ATL/MFC), a
>> tstring? [Or any other number of custom C++ string classes which may
>> exist in your code.] Or the unicode versions of any/all of those?

>> My recommendation: find out what the types *really* are in the
>> line you posted above. That'll usually help point you in the right
>> direction, as I bet you'll find that they're different.

>Its a CString.
>CString MachineName;

First, don't top-post. English is read left-to-right,
top-to-bottom. Trim off your replies to be just what you're
responding to.

Next, why bring up 'MachineName' when is not found in the code
snippet you gave above -- it's 'Name' and whatever GetAgentName()
returns. Also, note that I said to investigate the type*S* in that
line. Not 'type'. Plural. In your line about 'Name +=
blah->GetAgentName()', you need to look into the type*S* of the left
and right sides of that.

Nathan Mates
--
<*> Nathan Mates - personal webpage http://www.visi.com/~nathan/
# Programmer at Pandemic Studios -- http://www.pandemicstudios.com/
# NOT speaking for Pandemic Studios. "Care not what the neighbors
# think. What are the facts, and to how many decimal places?" -R.A. Heinlein

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Ben Voigt - 24 May 2007 22:39 GMT

>>> >After migrating my application from VC++ 6.0 to VC++ 2005, I receive
>>> >the
[quoted text clipped - 25 lines]
> blah->GetAgentName()', you need to look into the type*S* of the left
> and right sides of that.

Of course, this is SO fundamental to solving a "ambiguous function" error
that the compiler really should have told you that, along with the possible
matches it found. In fact, I think VC++ 2005 does exactly that.

Please cut+paste the following few lines from the compiler output, where it
gives the argument types along with the candidate functions.

> Nathan Mates
> --
[quoted text clipped - 3 lines]
> # think. What are the facts, and to how many decimal places?" -R.A.
> Heinlein

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Migrating from VC++ 6.0 to VC++ 2005

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