# OS_ReferentSize

## C Specification

      #include <nitro/os.h>

      void OS_ReferentSize( OSArenaId id, void* ptr );

## Arguments

id | ID of the arena associated with the memory block
ptr | Pointer to the memory block

## Return Values

Returns the size of the specified main block in memory, excluding the header region for managing the memory block.

## Description

Acquires the size that the specified main block occupies in memory, excluding the header region for managing the memory block.

id specifies the arena ID that contains the memory block. To read more about this value, see `OS_InitArena()`.

`ptr` is the address to the memory block that is previously acquired with `OS_AllocFixed()`, `OS_AllocFromHeap()`, etc.

## See Also

`OS_InitArena`, `OS_InitAlloc`, `OS_AllocFromHeap`, `OS_AllocFixed`

## Revision History

01/07/2004 Initial Version

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