30 Input/output library [input.output]

30.10 File systems [filesystems]

30.10.8 Class path [fs.class.path]

30.10.8.3 path requirements [fs.path.req]

In addition to the requirements ([fs.req]), function template parameters named Source shall be one of:

Functions taking template parameters named Source shall not participate in overload resolution unless either

[Note: See path conversions for how the value types above and their encodings convert to path​::​value_­type and its encoding. end note]

Arguments of type Source shall not be null pointers.