Realloc

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malloc

MALLOC(2)							System Calls Manual							 MALLOC(2)

NAME

       malloc, free, realloc, calloc - memory allocator

SYNOPSIS

       #include <u.h>
       #include <libc.h>

       void* malloc(long size)

       void  free(void *ptr)

       void* realloc(void *ptr, long size)

       void* calloc(long nelem, long elsize)

DESCRIPTION

       Malloc  and free provide a simple memory allocation package.  Malloc returns a pointer to a new block of at least size bytes.  The block is
       suitably aligned for storage of any type of object.  No two active pointers from malloc will have the same value.

       The argument to free is a pointer to a block previously allocated by malloc; this space is made available for further  allocation.   It	is
       legal to free a null pointer; the effect is a no-op.

       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.  The call realloc(0, size) means the same as

       Calloc allocates space for an array of nelem elements of size elsize.  The space is initialized to zeros.  Free frees such a block.

   Alef
       Except for calloc, these routines are available from Alef; they use the same arena as alloc.  Malloc and realloc execute a check when  they
       fail, rather than return nil.  Memory returned by malloc is cleared.  Realloc does not guarantee new memory is cleared unless ptr is nil.

SOURCE

       /sys/src/libc/port/malloc.c

SEE ALSO

       brk(2)

DIAGNOSTICS

       Malloc, realloc and calloc return 0 if there is no available memory.  Errstr is likely to be set.

BUGS

       The different specification of calloc is bizarre.

       User errors can corrupt the storage arena.  The most common gaffes are (1) freeing an already freed block, (2) storing beyond the bounds of
       an allocated block, and (3) freeing data that was not obtained from the allocator.  When malloc	and  free  detect  such  corruption,  they
       abort.

																	 MALLOC(2)

Programming