> Note that a function that has pointer arguments and examines the data pointed
to must not be declared const if the pointed-to data might change between
successive invocations of the function. In general, since a function cannot
distinguish data that might change from data that cannot, const functions should
never take pointer or, in C++, reference arguments. Likewise, a function that
calls a non-const function usually must not be const itself.
from [GCCdocumentation](https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attr
ibutes.html#index-const-function-attribute)