Can your mail client prompt you, if you forgot to attach a file?

How many times you have received any mail which says that there is a file attached, but there isn't any file attached. The sender has actually forgot to attach a file. Also, how many times you have sent such a mail?

Ya, things like this happens. So what could be the solution? Can we have a mail client intelligent enough to prompt us about missing attachment? Is this possible?

Looking at the problem, I can see a very simple solution. It goes like this:

Prompt user before sending a mail WHEN
the mail content HAS WORD like 'attached' or 'enclosed'
AND
there is NO attachment attached

Also, this check can only be performed, when user wants his mail client to prompt about missing attachment, by explicitly setting the related option in mail client preferences.

Looking at the mails I have received without attachments, and sometimes the delay caused because of that, I strongly feel that having such a feature will be really useful.

What's wrong with Sun Studio C++?

Don't be surprised if you are using multimap and your code is working on other standard C++ compilers and not on Sun Studio C++. e.g. See below code, which is correct according to C++ standards, but it will not compile on Sun Studio C++.

And if you use map instead of multimap it will work. But hey, you want to use multimap and not map, so what's wrong with Sun Studio C++?

#include <map>
#include <utility>

int main() {
std::map<int, int> mymap;
mymap.insert(std::make_pair(2, 4));

std::multimap<int, int> mymultimap;
mymultimap.insert(std::make_pair(2, 4));

return 0;
}


If you compile this code with Sun Studio (my version was forte v10.0p1), you probably will get error something like,

Error: Could not find a match for std::multimap<int, int, std::less<int>, std::allocator<std::pair<const int, int>>>::insert(std::pair<int, int>) needed in main().


The same code will compile perfectly fine with other standard C++ compilers. So, what's wrong with Sun Studio C++? Is something missing in Sun Studio?

OK, So to investigate it further, if you open <sun-studio-installation-directory>/prod/include/CC/Cstd/utility, you'll find

#ifndef _RWSTD_NO_MEMBER_TEMPLATES
template <class U, class V> pair(const pair<U,V>& p)
: first(p.first), second(p.second)
{ ; }
#endif

and in <sun-studio-installation-directory>/prod/include/CC/Cstd/stdcomp.h, you'll find

# define _RWSTD_NO_MEMBER_TEMPLATES 1


Since _RWSTD_NO_MEMBER_TEMPLATES is defined, member template copy constructor is not available. In case of map class it has function

pair<iterator, bool> insert (const pair<key_type, mapped_type> &__x)
{
return insert (pair<const key_type, mapped_type> (__x.first, __x.second));
}

therefore it works for map class.

In case of multimap, value_type is pair<const Key, T>, and since pair class lacks the templated copy constructor, insert can't convert pair<int, int> to pair<const int, int>, So we can use following work around:
1.

#include <map>
#include <utility>

int main() {
std::map<int, int> mymap;
mymap.insert(std::make_pair(2, 4));

std::multimap<int, int> mymultimap;
mymultimap.insert(std::pair<const int, int>(2, 4));

return 0;
}

2.

#include <map>
#include <utility>

int main() {
std::map<int, int> mymap;
mymap.insert(std::make_pair(2, 4));

typedef std::multimap<int, int> intmultimap;
intmultimap mymultimap;

mymultimap.insert(intmultimap::value_type(2,4));
return 0;
}

3.
If you don't want to change your existing code, you can use more standard-conforming library, by specifying option -library=stlport4, while compiling and linking.

Sun C++ FAQs indicates that they cannot update the standard library without breaking source and binary compatibility, so they will continue to ship a libCstd with the same limitations. I hope these workarounds will help you then.