MALLOC(3C-SVR4)     RISC/os Reference Manual      MALLOC(3C-SVR4)



NAME
     malloc, free, realloc, calloc, memalign, valloc - memory
          allocator

SYNOPSIS
     #include <stdlib.h>

     void *malloc (size_t size);

     void free (void *ptr);

     void *realloc (void *ptr, size_t size);

     void *calloc (size_t nelem, size_t elsize);

     void *memalign(size_t alignment, size_t size);

     void *valloc(size_t size);

DESCRIPTION
     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.  After free is per-
     formed this space is made available for further allocation.
     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.

     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.

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

     memalign allocates size bytes on a specified alignment boun-
     dary, and returns a pointer to the allocated block.  The
     value of the returned address is guaranteed to be an even
     multiple of alignment.  Note: the value of alignment must be
     a power of two, and must be greater than or equal to the
     size of a word.

     valloc(size) is equivalent to
     memalign(sysconf(_SC_PAGESIZE),size).




                        Printed 11/19/92                   Page 1

MALLOC(3C-SVR4)     RISC/os Reference Manual      MALLOC(3C-SVR4)



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

     malloc, realloc, calloc, memalign, and valloc will fail if
     there is not enough available memory.

SEE ALSO
     malloc(3X).

DIAGNOSTICS
     If there is no available memory, malloc, realloc, memalign,
     valloc, 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.







































 Page 2                 Printed 11/19/92