Re: [ALACPP] const char* NULL to std::string api

Hi Gavin!

Long time no talk to! Smiley emoticon

Anyway, I will throw out my weird solution (which might not work), and then you can do the same...hehe

How about:

void doFoo(const void *param)

{

if isStringRef( param ) // this may not be possible, killing solution

{

// treat as param const string&

return;

}

if isCharPtr( param ) // this may not be possible, killing solution

{

// treat as const char*

return;

}

// error

}

My two cents... Smiley emoticon

[==P==]

----- Original Message -----

From: Gavin Doughtie

To: alacpp@xxxxxxxxxxx

Sent: Wednesday, May 05, 2004 4:46 PM

Subject: [ALACPP] const char* NULL to std::string api

So an interesting puzzle came up at work today.

Say you have an API like so:

void doFoo(const char* param)
{
if (NULL != param) {
// do something
}
}

Great. Now say you want to be modern and write the api like so:

void doFoo(const std::string& param)
{
}

Now imagine that somebody calls you with a NULL const char* param. std::string tries to implicitly convert that NULL pointer to a std::string,
and, if you are lucky and your compiler isn't a leftover from the tech boom like it might be at certain entertainment companies, the string constructor
throws a logic_error.

There is no way to guard against this except by including a const char* implementation of your interface which does the appropriate checks before forwarding to the std::string
implementation.

The best I've come up with so far is some nasty boost::preprocessor macro to write the parellel implementation for you. Does anybody have a better idea?
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