Re: [boost] property tree find no match for 'operator=='

Subject: Re: [boost] property tree find no match for 'operator=='
From: Sebastian Redl (sebastian.redl_at_[hidden])
Date: 2011-09-30 14:11:32

On 30.09.2011, at 19:17, Bernd Prager wrote:

> All,
> 
> This is likely to be a silly question.
> I am trying to check for the existence of a value in a property tree.
> 
> Reading the docs I assumed the easiest way would be:
> 
> namespace pt = boost::property_tree;
> static pt::ptree pt;
> 
> bool has(const std::string key) {
>    if (pt.find(key) == pt.end()) return false;    // (1)
>    return true;
> }
> 
> The compiler complains about "error: no match for 'operator=='" in line
> (1) though.
> What am I missing?

Because of a peculiarity of PTree, the iterator returned by find() is not compatible with those returned by begin() and end(). You must compare with not_found() to get the result you want.

Sebastian