mapmalloc(3X)

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUES | FILES | ATTRIBUTES | SEE ALSO

NAME

mapmalloc- memory allocator

SYNOPSIS

cc [ flag ... ] file ... -lmapmalloc [ library ... ]
#include <stdlib.h>

void *malloc(size_t size);
void *calloc(size_t nelem, size_t elsize);
void free(void * ptr);
void *realloc(void *ptr, size_t size);

DESCRIPTION

The collection of malloc routines in this library use mmap(2) instead of sbrk(2) for acquiring new heap space. The routines in this library are intended to be used only if necessary, when applications must call sbrk(), but need to call other library routines that might call malloc. The algorithms used by these routines are not sophisticated. There is no reclaiming of memory.

malloc() and free() provide a simple general-purpose memory allocation package.

malloc() returns a pointer to a block of at least size bytes suitably aligned for any use.

The argument to free() is a pointer to a block previously allocated by malloc(), calloc() or realloc(). If ptr is a NULL pointer, no action occurs.

Undefined results will occur if the space assigned by malloc() is overrun or if some random number is handed to free().

calloc() allocates space for an array of nelem elements of size elsize. The space is initialized to zeros.

realloc() 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 ptr is NULL, realloc() behaves like malloc() for the specified size. If size is zero and ptr is not a null pointer, the object pointed to is freed.

Each of the allocation routines returns a pointer to space suitably aligned (after possible pointer coercion) for storage of any type of object.

malloc() and realloc() will fail if there is not enough available memory.

Entry points for malloc_debug(), mallocmap(), mallopt(), mallinfo(), memalign(), and valloc(), are empty routines, and are provided only to protect the user from mixing malloc() functions from different implementations.

RETURN VALUES

If there is no available memory, malloc(), realloc(), and calloc() return a null pointer. When realloc() returns NULL, the block pointed to by ptr is left intact. If size, nelem, or elsize is 0, a unique pointer to the arena is returned.

FILES

/usr/lib/libmapmalloc

ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE	ATTRIBUTE VALUE
MT-Level	Safe

SEE ALSO

brk(2), getrlimit(2), mmap(2), realloc(3C), malloc(3X), attributes(5)

SunOS 5.7  Last Revised 26 Mar 1998

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUES | FILES | ATTRIBUTES | SEE ALSO