22 Containers library [containers]

22.2 Container requirements [container.requirements]

22.2.1 General container requirements [container.requirements.general]

Table 75: Optional container operations [tab:container.opt]
Expression
Return type
Operational
Assertion/note
Complexity
semantics
pre-/post-condition
a <=> b
synth-three-​way-result<value_­type>
lexicographical_­compare_­three_­way(a.begin(), a.end(), b.begin(), b.end(), synth-three-way)
Preconditions: Either <=> is defined for values of type (possibly const) T, or < is defined for values of type (possibly const) T and < is a total ordering relationship.
linear