C++ standard sort documentation issue -

my copy of c++ standard document documents standard sort function.

25.4.1.1 sort

template<class randomaccessiterator> void sort(randomaccessiterator first, randomaccessiterator last); ... effects: sorts elements in range [first,last). 

requires: randomaccessiterator shall satisfy requirements of valueswappable (17.6.3.2). type of *first shall satisfy requirements of moveconstructible (table 20) , of moveassignable

ok - shouldn't require elements referred comparable?

i expect "requires" clause include like:

"type results dereferencing randomaccessiterator should satisfy requirements of lessthancomparable."

or better yet

"iterator_traits<randomaccessiterator>::value_type should satisfy requirements of lessthancomparable."

since 24.4.1 says in part "it required if iterator type of iterator, types ... iterator_traits<iterator>::value_type defined"

why isn't such language included. surely sort function can't sort elements can't compared.

• ok - shouldn't require elements referred comparable?

if scrolled above in standard have found these requirements (under § 25.4) sorting algorithms:

all operations in 25.4 have 2 versions: 1 takes function object of type compare , 1 uses operator<.

which means it's enforced in standard types required use operator< or custom comparator.

the custom comparator has following requirements:

compare function object type (20.8). return value of function call operation applied object of type compare, when contextually converted bool (4), yields true if first argument of call less second, , false otherwise. compare comp used throughout algorithms assuming ordering relation. assumed comp not apply non-constant function through dereferenced iterator.