template instance in shared library on sun 5.7

[John Dumais]

Hello,

I have a templated class defined in a header file and implemented in a
cpp
source file. The class is basically a little marshaler that contains a
factory method and a few marshaling functions. The template parameter
defines the type stored in a contained vector. That class is built into
a
shared library. The (condensed) code goes like this...

TypeMarshaler.h

#include <vector>
#include <string>

struct ITypeMarshaler
{
virtual void Marshal() = 0;
virtual void Unmarshal() = 0;
};

template <typename T>
class TypeMarshaler : public ITypeMarshaler
{
public:
virtual void Marshal();
virtual void Unmarshal();

private:
std::vector<T> dataValues;
};

class TypeMarshalerFa ctory
{
public:
static ITypeMarshaler* Create(const std::string &dataType);
};

TypeMarshaler.c pp

#include "TypeMarshaler. h"

ITypeMarshaler* TypeMarshalerFa ctory::Create(c onst std::string
&dataType)
{
// this is implemented using a map in the real code, but just so you
get
the idea...
if(dataType == "System.Int 32") { return new TypeMarshaler<l ong>; }
... and so on
}

template <typename T>
void TypeMarshaler<T >::Marshal()
{
...
}

template <typename T>
void TypeMarshaler<T >::Unmarshal( )
{
...
}

The client code looks like this and links against the shared library...

Client.cpp

#include "TypeMarshaler. h"

int main()
{
ITypeMarshaler *tm = TypeMarshalerFa ctory::Create(" System.Int32");

... use tm & do other stuff.

return 0;
}

The client does what I expect on HP-UX 11 using aCC, Linux using gcc,
Windows using MS VC 6 & 7. However, on Sun 5.7 using whatever the most
popular Sun-supplied compiler is, linking the client results in
unresolved
externals of the form...

std::vector<lon g, allocator_stuff <long> >::_M_fill_inse rt(...) first
referenced in libTypeMarshale r.so.

I would have thought that having the TypeMarshalerFa ctory::Create()
method
reference a data type in a "new" expression would have been good enough
to
get the contained vector type defined in the shared library, since
client
code doesn't directly reference the TypeMarshaler type.

Am I doing something fundamentally wrong?

Thanks,
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[tom_usenet]

On 8 Jul 2003 00:30:04 -0400, "John Dumais" <no***********@ sonic.net>
wrote:

The client does what I expect on HP-UX 11 using aCC, Linux using gcc,
Windows using MS VC 6 & 7. However, on Sun 5.7 using whatever the most
popular Sun-supplied compiler is, linking the client results in
unresolved
externals of the form...

std::vector<lo ng, allocator_stuff <long> >::_M_fill_inse rt(...) first
referenced in libTypeMarshale r.so.

You should ask in a sun newsgroup, since this is obviously a sun
specific problem. (hint -

-xar Creates archive libraries.

When building a C++ archive that uses templates,
it is necessary in most cases to include in the
archive those template functions that are instan-
tiated in the template repository. Using this
option automatically adds those templates to the
archive as needed.

Examples:

The following command archives the template func-
tions contained in the repository and the object
files.

% CC -xar -o libmain.a a.o b.o c.o

Warnings:

Do not add .o files from the template repository
on the command line.

Do not use the ar command directly for building
archives. Use CC -xar to ensure that template
instantiations are automatically included in the
archive.

)

Tom

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