1bsdmalloc(3MALLOC) Memory Allocation Library Functions bsdmalloc(3MALLOC)
2
6 bsdmalloc - memory allocator
7
9 cc [ flag ... ] file ... -lbsdmalloc [ library ... ]
10 char *malloc(sizeunsigned size;
12 int free( ptrchar *ptr;
15 char *realloc( ptr, sizechar *ptr;
18 unsigned size;
19
22 These routines provide a general-purpose memory allocation package.
23 They maintain a table of free blocks for efficient allocation and coa‐
24 lescing of free storage. When there is no suitable space already free,
25 the allocation routines call sbrk(2) to get more memory from the sys‐
26 tem. Each of the allocation routines returns a pointer to space suit‐
27 ably aligned for storage of any type of object. Each returns a null
28 pointer if the request cannot be completed.
29 The malloc() function returns a pointer to a block of at least size
32 bytes, which is appropriately aligned.
33 The free() function releases a previously allocated block. Its argument
36 is a pointer to a block previously allocated by malloc() or realloc().
37 The free() function does not set errno.
38 The realloc() function changes the size of the block pointed to by ptr
41 to size bytes and returns a pointer to the (possibly moved) block. The
42 contents will be unchanged up to the lesser of the new and old sizes.
43 If the new size of the block requires movement of the block, the space
44 for the previous instantiation of the block is freed. If the new size
45 is larger, the contents of the newly allocated portion of the block are
46 unspecified. If ptr is NULL, realloc() behaves like malloc() for the
47 specified size. If size is 0 and ptr is not a null pointer, the space
48 pointed to is freed.
49
51 The malloc() and realloc() functions return a null pointer if there is
52 not enough available memory. They return a non-null pointer if size is
53 0. These pointers should not be dereferenced. When realloc() returns
54 NULL, the block pointed to by ptr is left intact. Always cast the value
55 returned by malloc() and realloc().
56
58 If malloc() or realloc() returns unsuccessfully, errno will be set to
59 indicate the following:
60 ENOMEM size bytes of memory cannot be allocated because it exceeds
62 the physical limits of the system.
63 EAGAIN There is not enough memory available at this point in time to
66 allocate size bytes of memory; but the application could try
67 again later.
68
71 Using realloc() with a block freed before the most recent call to mal‐
72 loc() or realloc() results in an error.
73 Comparative features of the various allocation libraries can be found
76 in the umem_alloc(3MALLOC) manual page.
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79 brk(2), malloc(3C), malloc(3MALLOC), mapmalloc(3MALLOC),
80 umem_alloc(3MALLOC)
81
83 Use of libbsdmalloc renders an application non-SCD compliant.
84 The libbsdmalloc routines are incompatible with the memory allocation
87 routines in the standard C-library (libc): malloc(3C), alloca(3C), cal‐
88 loc(3C), free(3C), memalign(3C), realloc(3C), and valloc(3C).
89SunOS 5.11 21 Mar 2005 bsdmalloc(3MALLOC)