Is the pImpl idiom really used in practice?

Question

I am reading the book \"Exceptional C++\" by Herb Sutter, and in that book I have learned about the pImpl idiom. Basically, the idea is to create a structure for the p

Answer 1

I would mainly consider PIMPL for classes exposed to be used as an API by other modules. This has many benefits, as it makes recompilation of the changes made in the PIMPL implementation does not affect the rest of the project. Also, for API classes they promote a binary compatibility (changes in a module implementation do not affect clients of those modules, they don't have to be recompiled as the new implementation has the same binary interface - the interface exposed by the PIMPL).

As for using PIMPL for every class, I would consider caution because all those benefits come at a cost: an extra level of indirection is required in order to access the implementation methods.