The Windows API uses this scheme for one of its 50 string types [1]. I"m not very fond of this design as it's easy to pass a "normal" C string, which compiles

The Windows API uses this scheme for one of its 50 string types [1]. I"m not very fond of this design as it's easy to pass a "normal" C string, which compiles because BSTR is just a typedef to it. You can allocate the exact same data structure, but store a pointer to the size prefix, instead of the first byte - you avoid that issue, and can still pass the data field to anything expecting a zero-terminated string: struct WeirdString { int size; char data[0]; }; struct WeirdString* ws = ...; fopen(ws->data); [1] BSTR - https://learn.microsoft.com/en-us/previous-versions/windows/desktop/automat/bstr https://learn.microsoft.com/en-us/previous-versions/windows/...