How to set a conditional breakpoint for C++ strings in VS2019?

Question

I'm trying to set a conditional breakpoint for my debug but VS keeps returning me this error:

How can it be so if the operator != is defined for strings?

The variable error is std::string

Answer 1

There are many workarounds you can do, for example a much better way of writing your condition is this:

!errors.empty()

You also have size() that you can compare against 0, c_str() that returns a C string which you can test the first element against \0 , etc etc.

As to the reason why your line doesn't work is that most likely the conditional debugger can't resolve the overloaded operator. Perhaps checking against a non-implicitly built string (ie, error != string{} ) would work better, or using a newer VS version, but really you can see how wasteful that is instead of just simply checking the empty() function result.

Answer 2

Temporarily adding something like this to your code might do it:

const auto s = string_i_want_to_test_to_see_if_its_empty.c_str ();

and then for the conditional breakpoint, the expression would be:

s [0] != 0;

Put that breakpoint on the line immediately after the one added. Hopefully, in a Debug build, it won't get optimised out. If it does, I'm sure you'll think of a way round it.