mallocsizet

Mallocsizet is a typedef or alias used in some C and C++ codebases to denote the size of a memory block allocated by malloc and related functions. It is not part of the C or C++ standards and is not universally adopted, but it appears in projects that want to distinguish allocator-reported sizes from other size concepts.

Typically, mallocsizet is defined as an unsigned integer type chosen to be compatible with size_t. In practice, many codebases implement it as a typedef of size_t (for example, typedef size_t mallocsizet;), while others select a distinct underlying type to emphasize semantic meaning that a value represents an allocated block’s size.

Mallocsizet is often used in APIs that wrap or interact with malloc-like functions, where functions return or convey the size of allocated memory. It may also hold values obtained from allocator-specific queries, such as reporting the usable or actual allocated size for a given pointer. Because allocator behavior varies across platforms, the relationship between mallocsizet and the raw pointer size is not guaranteed to be uniform.

Portability considerations arise because mallocsizet is not standardized. For portable code, size_t is generally preferred for representing memory sizes, and allocator-specific functions (such as those that report usable or actual allocated sizes) should be used only when the target environment provides them.

See also:

- size_t

- malloc_usable_size

- malloc_size

- allocator-specific size queries

---