Valgrind Software Quick Start Manual page 83

• VALGRIND_MEMPOOL_ALLOC(pool, addr, size): This request informs Memcheck that a size-byte
chunk has been allocated at addr, and associates the chunk with the specified pool. If the pool was created
with nonzero rzB redzones, Memcheck will mark the rzB bytes before and after the chunk as NOACCESS. If
the pool was created with the is_zeroed argument set, Memcheck will mark the chunk as DEFINED, otherwise
Memcheck will mark the chunk as UNDEFINED.
• VALGRIND_MEMPOOL_FREE(pool, addr): This request informs Memcheck that the chunk at addr should
no longer be considered allocated. Memcheck will mark the chunk associated with addr as NOACCESS, and
delete its record of the chunk's existence.
• VALGRIND_MEMPOOL_TRIM(pool, addr, size): This request trims the chunks associated with pool.
The request only operates on chunks associated with pool. Trimming is formally defined as:
• All chunks entirely inside the range addr..(addr+size-1) are preserved.
• All chunks entirely
VALGRIND_MEMPOOL_FREE was called on them.
• All other chunks must intersect with the range addr..(addr+size-1); areas outside the intersection are
marked as NOACCESS, as though they had been independently freed with VALGRIND_MEMPOOL_FREE.
This is a somewhat rare request, but can be useful in implementing the type of mass-free operations common in
custom LIFO allocators.
• VALGRIND_MOVE_MEMPOOL(poolA, poolB): This request informs Memcheck that the pool previously
anchored at address poolA has moved to anchor address poolB. This is a rare request, typically only needed
if you realloc the header of a mempool.
No memory-status bits are altered by this request.
• VALGRIND_MEMPOOL_CHANGE(pool, addrA, addrB, size): This request informs Memcheck that the
chunk previously allocated at address addrA within pool has been moved and/or resized, and should be changed
to cover the region addrB..(addrB+size-1). This is a rare request, typically only needed if you realloc a
superblock or wish to extend a chunk without changing its memory-status bits.
No memory-status bits are altered by this request.
• VALGRIND_MEMPOOL_EXISTS(pool): This request informs the caller whether or not Memcheck is currently
tracking a mempool at anchor address pool. It evaluates to 1 when there is a mempool associated with that address,
0 otherwise. This is a rare request, only useful in circumstances when client code might have lost track of the set of
active mempools.
outside the range
addr..(addr+size-1)
Memcheck: a memory error detector
are discarded, as though
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