BSDMALLOC(3MALLOC)BSDMALLOC(3MALLOC)NAMEbsdmalloc - memory allocator
cc [ flag ... ] file ... -lbsdmalloc [ library ... ]
char *malloc(sizeunsigned size;
int free( ptrchar *ptr;
char *realloc( ptr, sizechar *ptr;
These routines provide a general-purpose memory allocation package.
They maintain a table of free blocks for efficient allocation and coa‐
lescing of free storage. When there is no suitable space already free,
the allocation routines call sbrk(2) to get more memory from the sys‐
tem. Each of the allocation routines returns a pointer to space suit‐
ably aligned for storage of any type of object. Each returns a null
pointer if the request cannot be completed.
The malloc() function returns a pointer to a block of at least size
bytes, which is appropriately aligned.
The free() function releases a previously allocated block. Its argument
is a pointer to a block previously allocated by malloc() or realloc().
The free() function does not set errno.
The realloc() function changes the size of the block pointed to by ptr
to size bytes and returns a pointer to the (possibly moved) block. The
contents will be unchanged up to the lesser of the new and old sizes.
If the new size of the block requires movement of the block, the space
for the previous instantiation of the block is freed. If the new size
is larger, the contents of the newly allocated portion of the block are
unspecified. If ptr is NULL, realloc() behaves like malloc() for the
specified size. If size is 0 and ptr is not a null pointer, the space
pointed to is freed.
The malloc() and realloc() functions return a null pointer if there is
not enough available memory. They return a non-null pointer if size is
0. These pointers should not be dereferenced. When realloc() returns
NULL, the block pointed to by ptr is left intact. Always cast the value
returned by malloc() and realloc().
If malloc() or realloc() returns unsuccessfully, errno will be set to
indicate the following:
size bytes of memory cannot be allocated because it exceeds
the physical limits of the system.
There is not enough memory available at this point in time to
allocate size bytes of memory; but the application could try
Using realloc() with a block freed before the most recent call to mal‐
loc() or realloc() results in an error.
Comparative features of the various allocation libraries can be found
in the umem_alloc(3MALLOC) manual page.
SEE ALSObrk(2), malloc(3C), malloc(3MALLOC), mapmalloc(3MALLOC),
Use of libbsdmalloc renders an application non-SCD compliant.
The libbsdmalloc routines are incompatible with the memory allocation
routines in the standard C-library (libc): malloc(3C), alloca(3C), cal‐
loc(3C), free(3C), memalign(3C), realloc(3C), and valloc(3C).
Mar 21, 2005 BSDMALLOC(3MALLOC)