[omniORB] _var Mapping Question

[Ken Feuerman]

Yes, it turns out that both T::_nil() and CORBA::is_nil() work for checking
an uninitialized T_var variable.  It looks as though the reason neither
worked for me when I sent the message is because of a typo:

	if (!CORBA::is_nil(myvar));  // oops!  extra semi-colon
		myvar->doSomething();

Thus I was always calling myvar->doSomething(), even with a "NULL" myvar.

Thanks again!

--Ken Feuerman.


At 05:49 PM 9/22/99 -0400, Bruce Visscher wrote:
>If this isn't a FAQ, it should be.
>
>Ken Feuerman wrote:
>> 
>> I'd like to do something like the following:
>> 
>> T_var myvar;  // empty initialization
>> 
>> try
>> {
>>     myvar = // Something that will likely throw
>> }
>> catch (...)
>> {
>>     // oh well, didn't really need myvar anyhow
>> }
>> 
>> if (myvar != "NULL")   // (**)
>
>You can use T::_nil() here.
>
>> {
>>     // do something with a non-"NULL" myvar
>> }
>> 
>> Basically, in the line marked by (**), I need to check if the T_var
>> variable was ever assigned to successfully within the try{} block.  Is
>> there some ORB-portable way to check if a T_var is still "empty
initialized"?
>> 
>> By the way, I tried (!CORBA::is_nil(myvar)) for (**) above, and that did
>> not seem to work.
>> 
>
>Exactly how did it fail?
>
>The following program prints "Hello world!" on my screen:
>
>#include <iostream>
>#include "foo.hh"
>
>int main() {
>    foo_var myvar;
>    if (CORBA::is_nil(myvar))
>        std::cout << "Hello world!";
>}
>
>Bruce
>
>
>