Value used to denote "not-a-position", guaranteed to be outside the range[0 .. bsl::string_view::max_size()].
range[0 .. bsl::string_view::max_size()]
Declared in <bdlb_stringviewutil.h>
<bdlb_stringviewutil.h>
static size_type const k_NPOS = bsl::string_view::npos;