Building a safe Rust wrapper over an unsafe C API
WHAT IT TESTS: FFI encapsulation patterns. OUTLINE: hide extern calls behind a safe module, own the resource in a struct with Drop calling the C free, return Result mapping C error codes, use NewType/NonNull and PhantomData.
WHAT IT TESTS: whether you can design a sound abstraction over raw C, the so-called sys/safe split. ANSWER OUTLINE: keep the raw extern declarations in a low-level sys layer, then expose a safe wrapper. Own each C resource in a struct holding the raw handle and implement Drop to call the C destructor, giving RAII. Convert C error codes or errno into Result with a typed error. Use NonNull, newtypes, and PhantomData for lifetimes, and uphold Send/Sync only when truly safe. RED FLAG: exposing raw pointers or skipping Drop, leaking resources.
Read the original → interview
- #rust
- #ffi
- #raii
- #error-handling
- #safe-wrapper
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