How do I check if a StringStream variable is empty/null?

Question

Just a quick question here guys. I\'ve been searching to no avail so far.

A bit more info here:

stringstream report_string;

report_string << \         


        

Answer 1

I know that this question is very old and already answered, but depending on the situation there might also be yet another approach worth considering:

When you are testing if a stringstream is empty, you properly intend to do something with either the individual strings or each line in the stringstream; thus you will most likely be using either the >> operator or std::getline on the stringstream... and if the stream is empty these simply have the value false, thus you could write:

stringstream report_string;

foo(report_string)// some functions which may or may not write to report_string

string single_report;//string to read to

bool empty=true;//First assume it was empty
while(getline(report_string,single_report))//Alternatively use report_string>>single_report if you don't want entire lines
{
    empty=false;//...it wasn't empty
    bar(single_report);//Do whatever you want to do with each individual appended line 
}

if (empty)
{
    //... whatever you want to do if the stream was empty goes here
}

It should be noted that this approach assumes that you were planning on cycling through the stringstream; if you were not, then this approach can't be used.