Re: static object in a function: what if the constructor throws?

From:

metafoo@gmail.com

Newsgroups:

comp.lang.c++.moderated

Date:

Fri, 16 May 2008 17:44:23 CST

Message-ID:

<d1fcc0d4-0ce9-4bb1-ae35-db55a988ad58@m3g2000hsc.googlegroups.com>

On May 15, 10:57 pm, Krzysztof Czainski <1czaj...@gmail.com> wrote:

[code]
class Singleton
{
   Singleton(); // may throw
public:
   static Singleton& getInstance()
   {
     static Singleton instance;
     return instance;
   }
//...

};

int main()
{
   try {
     Singleton& s = Singleton::getInstance();
     //...
   }
   catch(...) { /* ... */ }}

[/code]

Is it legal for the static variable constructor to throw?

Yes.

Would it throw during the first call to getInstance, or earlier,
or is it unspecified when?

The constructor isn't called until the first call to getInstance.

See 6.7/4:

"such an object is initialized the first time control passes through
its declaration; such an object is considered initialized upon the
completion of its initialization. If the initialization exits by
throwing an exception, the initialization is not complete, so it will
be tried again the next time control enters the declaration"

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