On Monday, 12 February 2018 at 05:33:16 UTC, Norm wrote: > I thought inout was supposed to take const or non-const > variants, so expected the original const char* s to work. The problem is in argument e: it's mutable, and strtod stores there a part of s, if s is const you end up with const data available for writing through e. Should be const(char)** e.