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Chris Hill · Guest

I'm pulling my hair out here. I have some code that works on a number
of platforms and compilers (gcc 2.96 and 3.x and also Sun Workshop
C++). It makes extensive use of auto_ptr value parameters to make
explicit that ownership of objects is being passed into functions.

So, littered around the code are functions of the form:

void foo(std::auto_ptr<T> t){...}

With the callers calling them as:

// do some stuff
// create T and pass it into foo
foo(std::auto_ptr<T>(new T));

However, some of the time I want to be able to default initialise
the values passed into the function, code like:

void foo(std::auto_ptr<T> t = std::auto_ptr<T>(new T)){...}

// call foo create a DerivedFromT
foo(std::auto_ptr<T>(new T));

// call foo use the default version of t
foo();

This all works on the *Nix compilers I've come across so far but fails
to compile on HP aCC (with -AA). The error message I get, for the
following example code is:

hump [82]% /opt/aCC/bin/aCC -AA t.cxxError 226: "t.cxx", line 18
#No appropriate function found for call of
'auto_ptr::auto_ptr'. Last viable candidate was
"std::auto_ptr<char>::auto_ptr(std::auto_ptr<char> &)"
["/opt/aCC/include_std/memory",
line 833]. Argument of type 'class auto_ptr<char>' could not
be converted to 'std::auto_ptr<char> &'.
wobble();
^^^^^^^^

The sample code is:

hump [84]% cat t.cxx
#include <memory>
using namespace std;

void wobble(
auto_ptr<char> c = auto_ptr<char>(new char)
)
{
}

int main(int argc, char** argv)
{
std::auto_ptr<char> c(
std::auto_ptr<char>(new char)
);

wobble(c);
wobble();

return 0;
}

Can anyone cast any light onto what I'm doing wrong, or how
I can go about giving these auto_ptr values default values.

:) Chris.

PS. I've tried googling for an answer but not come up with anything.

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