6 Jun
2005
6 Jun
'05
9:31 a.m.
Tim Goetze wrote:
I assumed your objects should just be accessed from Python, but it's
of course different if they are to be managed by Python.
You could introduce an additional layer of indirection: hold a
separate C++ object with a pointer from the Python-managed object.
[Clemens Ladisch]
You mean you want to omit \n and the quotes? That was always invalid
in both C and C++.
Tim Goetze wrote:
May compile fine, but like this a 100-line __asm__ goes well beyond my
pain threshold when it comes to readability and maintainability. Enter gcc version 3, which drops multi-line
inline assembly support.
The following compiles fine with gcc 3.3.3:
__asm__ ("nop\n"
"nop\n"); If your
external functions use the correct type (i.e., a pointer to
the base type), the compiler will automatically cast class pointers in
the correct way. Otherwise, you have to cast to the base type
yourself whenever you 'export' a pointer.
Believe me I have tried to come up with sensible solutions but there's
quite a lot more to it than just fixing a few thousand pointer casts.
Basically, you can't rectify the problem because the basic Python
Object type (from which my types are derived) is actually at a fixed
offset into a Python garbage-collected structure. The following is OK for an older g++:
void
Descriptor<AmpIV>::setup()
{
UniqueID = 1794;
...
}
but g++ since 4.0 wants this instead:
template <> void
Descriptor<AmpIV>::setup()
{
...
}
I cannot for the life of me imagine a good reason why "template <>"
should be necessary.
It's needed because
A) the standard says so;
B) Descriptor is still a template, even if all template parameters
happen to be specialized.
"setup()" was never declared as a template,
let alone one with an
empty template parameter.
I guess you don't want to hear it, but if setup() was declared as a
template, you would have to write something like this:
template <> template <class T> void
Descriptor<AmpIV>::setup<T>()
{ ... }
If this is indeed prescribed by the language standard,
I'll have a
very, very hard time getting over it.
For completely specialized templates, you can avoid the "template<>"
stuff like this:
typedef Descriptor<AmpIV> Amp4Descriptor; // no "template" needed here
void Amp4Descriptor::setup() {...}
It may not look like much but you have to understand
that to me
coding is also an exercise in aesthetics.
"aesthetics" is not a keyword in C++. ;-)
Regards,
Clemens