[boost] Re: name mangling scheme for tru64cxx65

From: Ian McCulloch (ianmcc_at_[hidden])
Date: 2004-08-25 11:06:16

Markus Schöpflin wrote:

> Hello!
> 
> Currently, the name mangling scheme used on this platform is the default
> one selected by the compiler. It turns out that this is a bad choice when
> compiling boost. The problem is illustrated by the following example:
> 
> ---%<---
> #include <iostream>
> using namespace std;
> 
> template <typename T> void foo(T const &x)
> {
>    cout << "1" << endl;
> }
> 
> template <typename T> void foo(T * const &x)
> {
>    cout << "2" << endl;
> }
> 
> int main()
> {
>    foo("abc");
>    return 0;
> }
> --->%---
> 
> This prints out "2" with the default name mangling scheme. When manually
> selecting "ansi" as the name mangling scheme, the correct result "1" is
> printed.
> 
> Therefore I propose to explicitely set the name mangling to ansi in the
> tools file for this compiler. Does anyone have any strong feelings or
> arguments against such a change?

probably "-model ansi" is sufficient, and IMO absolutely necessary.  IIRC
correctly, there are issues with class-scope enumerations colliding, and in
the past I also had a problem with non-type template parameters that I
can't remember the details of just now.

>From the cxx man page:

-model [ansi | arm]

 [Tru64] Determines the layout of C++ classes, name mangling, and exception
handling. On Tru64 UNIX, the default is -model arm; on Linux Alpha, the
default is -model ansi. The -model arm option is not supported on Linux
Alpha. 

The -model arm option is the default and generates objects that are link
compatible with all Compaq C++ releases prior to Version 6.3, and with all
objects compiled using the -model arm option in Compaq C++ Version 6.3 or
later. Specifying this option defines the macro __MODEL_ARM. 

The -model ansi option supports the complete ISO/ANSI C++ specification,
including distinct name mangling for templates. The ANSI model also reduces
the size of C++ non-POD class objects. Note that this option generates
objects that are not compatible with prior releases of Compaq C++, or with
objects compiled using the -model arm option. 

If you specify the -model ansi option, you must recompile your entire
application, including libraries. Specifying this option defines the macro
__MODEL_ANSI. 

HTH,
Ian McCulloch