# Memory access in translated C

Files marked `@[translated]` retain C field mutability and pointer indexing rules.
Struct fields can be updated without V's `mut:` field annotation. A pointer into
an allocation can use a negative offset to access an earlier element in that
same allocation. Arrays still reject negative indexes.

These compatibility rules apply to expressions in the translated file. Ordinary
V files keep their usual field mutability and indexing checks, including when
using types declared by a translated file.

Translated code may also write through pointers returned by functions, including
pointers that alias another value. Its parameter and local names may shadow global
variables, as in C. Ordinary V files retain the alias and global-shadowing checks.

The address of a callback variable, field, or array element refers to its original
function-pointer slot. Parentheses around the addressed operand preserve this storage identity.