Total order on keys. Returns <0, 0, >0 for a ordering
before / equal to / after b. Must be pure; a and b are
exactly key_len bytes. ctx is the caller's opaque context,
threaded through every comparison unchanged.
| Type | Intent | Optional | Attributes | Name | ||
|---|---|---|---|---|---|---|
| character(len=*), | intent(in) | :: | a | |||
| character(len=*), | intent(in) | :: | b | |||
| class(*), | intent(in) | :: | ctx |