error: ‘make_unique’ is not a member of ‘g2o’

This error indicates that the 'make_unique' function is not recognized as a member of the 'g2o' namespace. The 'make_unique' function is a C++14 feature that is used to create a unique_ptr object with a dynamically allocated object.

To resolve this error, you can try a few potential solutions:

1. Update your compiler: Make sure you are using a C++14-compliant compiler that supports the 'make_unique' function. If you're using an older compiler version, it may not recognize this function. Upgrading to a newer version or enabling C++14 support in your current compiler might solve the issue.

2. Check g2o version: Verify that you are using a version of g2o that supports C++14. Older versions of g2o might not have implemented the 'make_unique' function. If necessary, update to a newer version of g2o that supports C++14.

3. Use alternative implementations: If upgrading your compiler or g2o version is not feasible, you can consider using alternative implementations for creating unique_ptr objects. Instead of 'make_unique', you can use 'std::unique_ptr' directly with 'new' to allocate and initialize the object.

Here's an example of using 'std::unique_ptr' instead of 'make_unique':

std::unique_ptr<YourObjectType> ptr(new YourObjectType());

Remember to replace 'YourObjectType' with the actual type you want to allocate.

By applying one of these solutions, you should be able to resolve the error and use the 'make_unique' function in your code successfully.