#### 19.2.2.5 Common Case in Pathname Components

For the functions in Figure~19–2, a value of `:common` for the `:case` argument that these functions should receive and yield strings in component values according to the following conventions:

`*`

  All uppercase means to use a file system’s customary case.

`*`

  All lowercase means to use the opposite of the customary case.

`*`

  Mixed case represents itself.

Note that these conventions have been chosen in such a way that translation from `:local` to `:common` and back to `:local` is information-preserving.