30 Input/output library [input.output]

30.10 File systems [filesystems]

30.10.7 Class path [fs.class.path]

30.10.7.3 path requirements [fs.path.req]

In addition to the requirements ([fs.req]), function template parameters named Source shall be one of:
  • basic_­string<EcharT, traits, Allocator>.
    A function argument const Source& source shall have an effective range [source.begin(), source.end()).
  • basic_­string_­view<EcharT, traits>.
    A function argument const Source& source shall have an effective range [source.begin(), source.end()).
  • A type meeting the input iterator requirements that iterates over a NTCTS.
    The value type shall be an encoded character type.
    A function argument const Source& source shall have an effective range [source, end) where end is the first iterator value with an element value equal to iterator_­traits<Source>​::​value_­type().
  • A character array that after array-to-pointer decay results in a pointer to the start of a NTCTS.
    The value type shall be an encoded character type.
    A function argument const Source& source shall have an effective range [source, end) where end is the first iterator value with an element value equal to iterator_­traits<decay_­t<Source>>​::​value_­type().
Functions taking template parameters named Source shall not participate in overload resolution unless either
  • Source is a specialization of basic_­string or basic_­string_­view, or
  • the qualified-id iterator_­traits<decay_­t<Source>>​::​value_­type is valid and denotes a possibly const encoded character type ([temp.deduct]).
[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.