-// but as a *string* in the form "x_y" where x is the major version
-// number and y is the minor version number. This is used by
-// <config/auto_link.hpp> to select which library version to link to.
+// but as a *string* in the form "x_y[_z]" where x is the major version
+// number, y is the minor version number, and z is the patch level if not 0.
+// This is used by <config/auto_link.hpp> to select which library version to link to.