These functions aren't safe to call from interrupt handlers; they may block on semaphores.
The Be Book - Special Topics - Device Drivers
Declared in: drivers/area_malloc.h
The area_malloc module provides a means for your driver to allocate
memory in areas instead of on the heap. It provides
malloc(),
calloc(),
realloc(),
and free()
functions that work just like their POSIX
counterparts, except they require a pool argument as their first input.
These functions aren't safe to call from interrupt handlers; they may block on semaphores.
The area_malloc functions are thread-safe in relation to one another, but
not in relation to
delete_pool().
Be sure you don't call
delete_pool()
on the pool you're using until you know none of the other functions might be
called.
create_pool()
and delete_pool()
are safe in relation to each other.
When the last user of the module puts it away, any remaining pools are automatically deleted.
const void* create_pool(uint32 addressSpec,
size_t size,
uint32 lockSpec,
uint32 protection);status_t delete_pool(const void* poolID);create_pool() creates a new pool of memory from which to allocate. The
parameters are the same as those used by
create_area(),
so you have complete control over the area's characteristics (except for its name).
Returns an opaque pool idenfityer, or NULL if the creation failed. The
ability to share resources allocated from the pool is determined by the
permissions and protections used to create the area.
delete_pool() deletes the pool specified by the
opaque poolID given. Any pointers returned by the
other functions in the module are immediately invalid. Returns
B_OK if the pool was deleted, otherwise
B_ERROR.
void* malloc(const void* poolID,
size_t size);void* calloc(const void* poolID,
size_t numMembers,
size_t size);void* realloc(const void* poolID,
void* ptr,
size_t size);malloc() allocates a block of
size bytes and returns a pointer to it.
calloc() allocates a block that can contain
numMembers items of the specified
size and returns a poiner to it.
realloc() resizes the memory block pointed to by
ptr to the indicated size.
Resizing a block can require that the memory be relocated, so this function
returns the new pointer.
Each of these operations functions in the pool specified by
poolID.
If there's not enough memory to allocate the requested block, these
functions return NULL.
